diff --git a/v2/crates/wifi-densepose-sensing-server/src/semantic/bed_exit.rs b/v2/crates/wifi-densepose-sensing-server/src/semantic/bed_exit.rs
new file mode 100644
index 00000000..1eed5bbc
--- /dev/null
+++ b/v2/crates/wifi-densepose-sensing-server/src/semantic/bed_exit.rs
@@ -0,0 +1,147 @@
+//! Bed-exit (overnight) primitive (§3.12.1 row 8).
+//!
+//! Edge-triggered event: fires once when "someone sleeping" transitions
+//! to "no presence in any bed-tagged zone" between 22:00 and 06:00
+//! local time.
+//!
+//! Inputs:
+//! - `sleeping` from upstream (the someone_sleeping primitive — wired
+//!   into the bus output so we don't re-derive it here)
+//! - `active_zones` — list of zones currently reporting presence
+//! - `bed_zones` — config list of zones tagged as bed-areas
+//! - `local_seconds_since_midnight` — local-time of day
+//!
+//! For v1 we don't have direct cross-primitive wiring, so we
+//! approximate "sleeping" with: was-presence-in-bed-zone, then
+//! exited-bed-zone. Refine in v2 when the bus exposes `sleeping`
+//! state to other primitives.
+
+use super::common::{in_window, PrimitiveConfig, PrimitiveState, RawSnapshot, Reason};
+
+#[derive(Debug, Default, Clone)]
+pub struct BedExit {
+    in_bed: bool,
+}
+
+impl BedExit {
+    pub fn new() -> Self { Self::default() }
+
+    fn in_bed_zone(snap: &RawSnapshot) -> bool {
+        !snap.bed_zones.is_empty()
+            && snap.active_zones.iter().any(|z| snap.bed_zones.contains(z))
+    }
+
+    pub fn tick(&mut self, snap: &RawSnapshot, cfg: &PrimitiveConfig) -> PrimitiveState {
+        if snap.since_start < cfg.warmup {
+            return PrimitiveState::Idle;
+        }
+        let now_in_bed = snap.presence && Self::in_bed_zone(snap);
+        let was_in_bed = self.in_bed;
+        self.in_bed = now_in_bed;
+
+        if was_in_bed && !now_in_bed {
+            // Only fire during overnight window.
+            let (start, end) = cfg.bed_exit_window;
+            if in_window(snap.local_seconds_since_midnight, start, end) {
+                return PrimitiveState::Event {
+                    event_type: "bed_exit",
+                    reason: Reason::new(&[
+                        "left_bed_zone",
+                        "overnight_window",
+                    ]),
+                };
+            }
+        }
+        PrimitiveState::Idle
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::time::Duration;
+
+    fn cfg() -> PrimitiveConfig { PrimitiveConfig::default() }
+
+    fn in_bed_overnight(t: u64) -> RawSnapshot {
+        RawSnapshot {
+            since_start: Duration::from_secs(120 + t),
+            presence: true,
+            active_zones: vec!["bedroom".into()],
+            bed_zones: vec!["bedroom".into()],
+            local_seconds_since_midnight: 2 * 3600, // 02:00
+            ..Default::default()
+        }
+    }
+
+    fn out_of_bed_overnight(t: u64) -> RawSnapshot {
+        RawSnapshot {
+            since_start: Duration::from_secs(120 + t),
+            presence: true,
+            active_zones: vec!["hall".into()],
+            bed_zones: vec!["bedroom".into()],
+            local_seconds_since_midnight: 2 * 3600,
+            ..Default::default()
+        }
+    }
+
+    #[test]
+    fn fires_on_bed_to_non_bed_overnight() {
+        let mut p = BedExit::new();
+        let _ = p.tick(&in_bed_overnight(10), &cfg());
+        let state = p.tick(&out_of_bed_overnight(20), &cfg());
+        assert!(matches!(state, PrimitiveState::Event { event_type: "bed_exit", .. }));
+    }
+
+    #[test]
+    fn does_not_fire_during_day() {
+        let mut p = BedExit::new();
+        let mut s_in = in_bed_overnight(10);
+        s_in.local_seconds_since_midnight = 14 * 3600; // 14:00
+        let _ = p.tick(&s_in, &cfg());
+        let mut s_out = out_of_bed_overnight(20);
+        s_out.local_seconds_since_midnight = 14 * 3600;
+        let state = p.tick(&s_out, &cfg());
+        assert!(matches!(state, PrimitiveState::Idle));
+    }
+
+    #[test]
+    fn does_not_fire_without_prior_in_bed() {
+        let mut p = BedExit::new();
+        // Person never was in bed.
+        let state = p.tick(&out_of_bed_overnight(20), &cfg());
+        assert!(matches!(state, PrimitiveState::Idle));
+    }
+
+    #[test]
+    fn warmup_blocks_initial_transitions() {
+        let mut p = BedExit::new();
+        let mut s_in = in_bed_overnight(0);
+        s_in.since_start = Duration::from_secs(30);
+        assert!(matches!(p.tick(&s_in, &cfg()), PrimitiveState::Idle));
+    }
+
+    #[test]
+    fn does_not_fire_when_bed_zones_unconfigured() {
+        let mut p = BedExit::new();
+        let mut s_in = in_bed_overnight(10);
+        s_in.bed_zones.clear();
+        let _ = p.tick(&s_in, &cfg());
+        let mut s_out = out_of_bed_overnight(20);
+        s_out.bed_zones.clear();
+        let state = p.tick(&s_out, &cfg());
+        assert!(matches!(state, PrimitiveState::Idle));
+    }
+
+    #[test]
+    fn fires_just_after_midnight_window_start() {
+        let mut p = BedExit::new();
+        let mut s_in = in_bed_overnight(10);
+        s_in.local_seconds_since_midnight = 22 * 3600 + 5; // 22:00:05
+        let _ = p.tick(&s_in, &cfg());
+        let mut s_out = out_of_bed_overnight(20);
+        s_out.local_seconds_since_midnight = 22 * 3600 + 10;
+        let state = p.tick(&s_out, &cfg());
+        assert!(matches!(state, PrimitiveState::Event { .. }));
+    }
+}
diff --git a/v2/crates/wifi-densepose-sensing-server/src/semantic/bus.rs b/v2/crates/wifi-densepose-sensing-server/src/semantic/bus.rs
index 651ade7c..ddd1bb5d 100644
--- a/v2/crates/wifi-densepose-sensing-server/src/semantic/bus.rs
+++ b/v2/crates/wifi-densepose-sensing-server/src/semantic/bus.rs
@@ -9,17 +9,33 @@
 //! add primitives in P4.5b.
 
 use super::common::{PrimitiveConfig, PrimitiveState, RawSnapshot, Reason};
-use super::{bathroom::BathroomOccupied, no_movement::NoMovement, room_active::RoomActive, sleeping::SomeoneSleeping};
+use super::{
+    bathroom::BathroomOccupied,
+    bed_exit::BedExit,
+    distress::PossibleDistress,
+    elderly_anomaly::ElderlyInactivityAnomaly,
+    fall_risk::FallRiskElevated,
+    meeting::MeetingInProgress,
+    multi_room::MultiRoomTransition,
+    no_movement::NoMovement,
+    room_active::RoomActive,
+    sleeping::SomeoneSleeping,
+};
 
 /// Identifier for which primitive produced an event. Used by the
 /// publisher to map onto the matching `EntityKind`.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum SemanticKind {
     SomeoneSleeping,
+    PossibleDistress,
     RoomActive,
+    ElderlyAnomaly,
+    Meeting,
     BathroomOccupied,
+    FallRisk,
+    BedExit,
     NoMovement,
-    // P4.5b: Distress, ElderlyAnomaly, Meeting, FallRisk, BedExit, MultiRoom.
+    MultiRoom,
 }
 
 /// One event published to MQTT / Matter consumers.
@@ -34,9 +50,15 @@ pub struct SemanticEvent {
 /// Collection of every primitive FSM. Owned by the publisher task.
 pub struct SemanticBus {
     sleeping: SomeoneSleeping,
+    distress: PossibleDistress,
     room_active: RoomActive,
+    elderly_anomaly: ElderlyInactivityAnomaly,
+    meeting: MeetingInProgress,
     bathroom: BathroomOccupied,
+    fall_risk: FallRiskElevated,
+    bed_exit: BedExit,
     no_movement: NoMovement,
+    multi_room: MultiRoomTransition,
     pub config: PrimitiveConfig,
 }
 
@@ -44,9 +66,15 @@ impl SemanticBus {
     pub fn new(config: PrimitiveConfig) -> Self {
         Self {
             sleeping: SomeoneSleeping::new(),
+            distress: PossibleDistress::new(),
             room_active: RoomActive::new(),
+            elderly_anomaly: ElderlyInactivityAnomaly::new(),
+            meeting: MeetingInProgress::new(),
             bathroom: BathroomOccupied::new(),
+            fall_risk: FallRiskElevated::new(),
+            bed_exit: BedExit::new(),
             no_movement: NoMovement::new(),
+            multi_room: MultiRoomTransition::new(),
             config,
         }
     }
@@ -54,11 +82,17 @@ impl SemanticBus {
     /// Run all primitives on one snapshot. Returns only events that
     /// emit (Idle states are filtered).
     pub fn tick(&mut self, snap: &RawSnapshot) -> Vec<SemanticEvent> {
-        let pairs: [(SemanticKind, PrimitiveState); 4] = [
-            (SemanticKind::SomeoneSleeping, self.sleeping.tick(snap, &self.config)),
-            (SemanticKind::RoomActive,      self.room_active.tick(snap, &self.config)),
-            (SemanticKind::BathroomOccupied, self.bathroom.tick(snap, &self.config)),
-            (SemanticKind::NoMovement,      self.no_movement.tick(snap, &self.config)),
+        let pairs: [(SemanticKind, PrimitiveState); 10] = [
+            (SemanticKind::SomeoneSleeping,   self.sleeping.tick(snap, &self.config)),
+            (SemanticKind::PossibleDistress,  self.distress.tick(snap, &self.config)),
+            (SemanticKind::RoomActive,        self.room_active.tick(snap, &self.config)),
+            (SemanticKind::ElderlyAnomaly,    self.elderly_anomaly.tick(snap, &self.config)),
+            (SemanticKind::Meeting,           self.meeting.tick(snap, &self.config)),
+            (SemanticKind::BathroomOccupied,  self.bathroom.tick(snap, &self.config)),
+            (SemanticKind::FallRisk,          self.fall_risk.tick(snap, &self.config)),
+            (SemanticKind::BedExit,           self.bed_exit.tick(snap, &self.config)),
+            (SemanticKind::NoMovement,        self.no_movement.tick(snap, &self.config)),
+            (SemanticKind::MultiRoom,         self.multi_room.tick(snap, &self.config)),
         ];
         pairs
             .into_iter()
diff --git a/v2/crates/wifi-densepose-sensing-server/src/semantic/distress.rs b/v2/crates/wifi-densepose-sensing-server/src/semantic/distress.rs
new file mode 100644
index 00000000..d0b380e1
--- /dev/null
+++ b/v2/crates/wifi-densepose-sensing-server/src/semantic/distress.rs
@@ -0,0 +1,284 @@
+//! Possible-distress primitive (§3.12.1 row 2).
+//!
+//! Enter `possible_distress = ON` when ALL of the following hold for
+//! `distress_dwell` (default 60 s):
+//! - sustained HR > `distress_hr_multiple` × rolling baseline (default 1.5×)
+//! - motion is agitated (motion > 0.20)
+//! - no fall recently
+//!
+//! Exit when HR returns to baseline OR motion calms below 0.10 for 30 s.
+//! After exit there's a 5-min latch suppressing re-fire (refractory).
+//!
+//! Baseline is an exponential moving average over a long window so a
+//! single high-HR sample doesn't shift the reference fast. Window is
+//! parametric so deployments can tune for resident demographics.
+
+use std::time::Duration;
+
+use super::common::{PrimitiveConfig, PrimitiveState, RawSnapshot, Reason};
+
+const REFRACTORY: Duration = Duration::from_secs(300);
+
+/// Exponential moving average over heart-rate samples.
+#[derive(Debug, Default, Clone)]
+struct Ewma {
+    value: Option<f64>,
+    alpha: f64, // 0..1, smaller = longer memory
+}
+
+impl Ewma {
+    fn new(alpha: f64) -> Self { Self { value: None, alpha } }
+    fn update(&mut self, x: f64) {
+        self.value = Some(match self.value {
+            Some(v) => self.alpha * x + (1.0 - self.alpha) * v,
+            None => x,
+        });
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct PossibleDistress {
+    pub active: bool,
+    baseline: Ewma,
+    enter_since: Option<Duration>,
+    last_exit: Option<Duration>,
+}
+
+impl Default for PossibleDistress {
+    fn default() -> Self {
+        Self {
+            active: false,
+            baseline: Ewma::new(0.01), // ~100-sample memory at 1 Hz
+            enter_since: None,
+            last_exit: None,
+        }
+    }
+}
+
+impl PossibleDistress {
+    pub fn new() -> Self { Self::default() }
+
+    pub fn tick(&mut self, snap: &RawSnapshot, cfg: &PrimitiveConfig) -> PrimitiveState {
+        if snap.since_start < cfg.warmup {
+            // Still seed the baseline even in warmup so we don't fire
+            // immediately after the warmup ends with a cold baseline.
+            if let Some(hr) = snap.heart_rate_bpm {
+                if snap.vital_confidence >= 0.5 { self.baseline.update(hr); }
+            }
+            return PrimitiveState::Idle;
+        }
+
+        let hr = match snap.heart_rate_bpm {
+            Some(v) if snap.vital_confidence >= 0.5 => v,
+            _ => return PrimitiveState::Idle,
+        };
+        let baseline = match self.baseline.value {
+            Some(b) if b > 0.0 => b,
+            _ => {
+                self.baseline.update(hr);
+                return PrimitiveState::Idle;
+            }
+        };
+
+        let hr_high = hr / baseline >= cfg.distress_hr_multiple;
+        let agitated = snap.motion > 0.20;
+        let no_fall = !snap.fall_detected;
+
+        // Only update baseline when NOT active AND NOT in a candidate
+        // distress event (low motion, HR near baseline). This keeps the
+        // baseline anchored to resting HR rather than chasing elevated
+        // samples — without this guard a sustained elevated HR drifts
+        // the baseline up before the dwell completes.
+        if !self.active && !agitated && !hr_high {
+            self.baseline.update(hr);
+        }
+
+        if !self.active {
+            // Refractory period after recent exit.
+            if let Some(t) = self.last_exit {
+                if snap.since_start.saturating_sub(t) < REFRACTORY {
+                    return PrimitiveState::Idle;
+                }
+            }
+            if hr_high && agitated && no_fall {
+                let start = *self.enter_since.get_or_insert(snap.since_start);
+                if snap.since_start.saturating_sub(start) >= cfg.distress_dwell {
+                    self.active = true;
+                    return PrimitiveState::Boolean {
+                        active: true,
+                        changed: true,
+                        reason: Reason::new(&[
+                            "hr_high>=1.5x",
+                            "motion>20%",
+                            "no_fall",
+                            "dwell>=60s",
+                        ]),
+                    };
+                }
+            } else {
+                self.enter_since = None;
+            }
+            PrimitiveState::Idle
+        } else {
+            // Active — check exit.
+            let calm = snap.motion < 0.10 && hr / baseline < 1.2;
+            if calm {
+                self.active = false;
+                self.enter_since = None;
+                self.last_exit = Some(snap.since_start);
+                return PrimitiveState::Boolean {
+                    active: false,
+                    changed: true,
+                    reason: Reason::new(&["motion<10%", "hr_back_to_baseline"]),
+                };
+            }
+            PrimitiveState::Idle
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn cfg() -> PrimitiveConfig { PrimitiveConfig::default() }
+
+    fn snap(t_secs: u64, hr: Option<f64>, motion: f64) -> RawSnapshot {
+        RawSnapshot {
+            since_start: Duration::from_secs(t_secs),
+            presence: true,
+            motion,
+            heart_rate_bpm: hr,
+            vital_confidence: 0.8,
+            ..Default::default()
+        }
+    }
+
+    fn seed_baseline(p: &mut PossibleDistress, hr: f64) {
+        // Warmup samples seed the EWMA baseline.
+        for t in 0..60 {
+            let _ = p.tick(&snap(t, Some(hr), 0.0), &cfg());
+        }
+    }
+
+    #[test]
+    fn does_not_fire_with_normal_hr() {
+        let mut p = PossibleDistress::new();
+        seed_baseline(&mut p, 70.0);
+        // Normal HR + low motion → no fire.
+        for t in 60..200 {
+            let s = snap(t, Some(72.0), 0.05);
+            assert!(matches!(p.tick(&s, &cfg()), PrimitiveState::Idle));
+        }
+        assert!(!p.active);
+    }
+
+    #[test]
+    fn fires_on_sustained_elevated_hr_with_motion() {
+        let mut p = PossibleDistress::new();
+        seed_baseline(&mut p, 70.0);
+        // Elevated HR (>1.5×70=105) + agitated motion, sustained 60s.
+        let mut fired = false;
+        for t in 60..200 {
+            let s = snap(t, Some(120.0), 0.35);
+            if matches!(p.tick(&s, &cfg()), PrimitiveState::Boolean { active: true, .. }) {
+                fired = true;
+                break;
+            }
+        }
+        assert!(fired, "primitive must fire on sustained elevated HR + motion");
+        assert!(p.active);
+    }
+
+    #[test]
+    fn does_not_fire_during_fall() {
+        let mut p = PossibleDistress::new();
+        seed_baseline(&mut p, 70.0);
+        for t in 60..200 {
+            let mut s = snap(t, Some(120.0), 0.35);
+            s.fall_detected = true;
+            assert!(matches!(p.tick(&s, &cfg()), PrimitiveState::Idle));
+        }
+        assert!(!p.active);
+    }
+
+    #[test]
+    fn exits_when_motion_calms_and_hr_normalises() {
+        let mut p = PossibleDistress::new();
+        seed_baseline(&mut p, 70.0);
+        // Trigger.
+        for t in 60..200 {
+            let s = snap(t, Some(120.0), 0.35);
+            let _ = p.tick(&s, &cfg());
+        }
+        assert!(p.active);
+        // Calm sample.
+        let s_calm = snap(220, Some(75.0), 0.05);
+        let state = p.tick(&s_calm, &cfg());
+        match state {
+            PrimitiveState::Boolean { active, changed, .. } => {
+                assert!(!active && changed);
+            }
+            other => panic!("expected off/change, got {:?}", other),
+        }
+        assert!(!p.active);
+    }
+
+    #[test]
+    fn refractory_blocks_immediate_refire() {
+        let mut p = PossibleDistress::new();
+        seed_baseline(&mut p, 70.0);
+        for t in 60..200 {
+            let _ = p.tick(&snap(t, Some(120.0), 0.35), &cfg());
+        }
+        // Calm to exit.
+        let _ = p.tick(&snap(220, Some(75.0), 0.05), &cfg());
+        assert!(!p.active);
+        // Try to re-fire 1 min after exit (refractory is 5 min).
+        for t in 280..400 {
+            let s = snap(t, Some(120.0), 0.35);
+            assert!(matches!(p.tick(&s, &cfg()), PrimitiveState::Idle));
+        }
+        assert!(!p.active);
+    }
+
+    #[test]
+    fn refire_allowed_after_refractory() {
+        let mut p = PossibleDistress::new();
+        seed_baseline(&mut p, 70.0);
+        for t in 60..200 {
+            let _ = p.tick(&snap(t, Some(120.0), 0.35), &cfg());
+        }
+        let _ = p.tick(&snap(220, Some(75.0), 0.05), &cfg());
+        // 6 min later — past refractory.
+        let mut fired = false;
+        for t in 600..800 {
+            let s = snap(t, Some(120.0), 0.35);
+            if matches!(p.tick(&s, &cfg()), PrimitiveState::Boolean { active: true, .. }) {
+                fired = true;
+                break;
+            }
+        }
+        assert!(fired);
+    }
+
+    #[test]
+    fn baseline_does_not_track_during_active() {
+        let mut p = PossibleDistress::new();
+        seed_baseline(&mut p, 70.0);
+        let initial = p.baseline.value.unwrap();
+        for t in 60..200 {
+            let _ = p.tick(&snap(t, Some(120.0), 0.35), &cfg());
+        }
+        assert!(p.active);
+        // Many more elevated samples — baseline must not climb.
+        for t in 200..400 {
+            let _ = p.tick(&snap(t, Some(130.0), 0.35), &cfg());
+        }
+        let after = p.baseline.value.unwrap();
+        // Baseline may move a little during pre-trigger window, but it
+        // must not chase the 130-bpm samples during the active state.
+        assert!(after < 100.0, "baseline {} drifted toward distress HR", after);
+        assert!(initial < 100.0);
+    }
+}
diff --git a/v2/crates/wifi-densepose-sensing-server/src/semantic/elderly_anomaly.rs b/v2/crates/wifi-densepose-sensing-server/src/semantic/elderly_anomaly.rs
new file mode 100644
index 00000000..104ef936
--- /dev/null
+++ b/v2/crates/wifi-densepose-sensing-server/src/semantic/elderly_anomaly.rs
@@ -0,0 +1,173 @@
+//! Elderly inactivity anomaly primitive (§3.12.1 row 4).
+//!
+//! Enter `elderly_inactivity_anomaly = ON` when current inactivity
+//! duration exceeds `elderly_anomaly_multiple` × rolling median of
+//! daily idle durations (default 2×).
+//!
+//! v1 implements this with a simplified rolling-quantile: the longest
+//! idle stretch ever seen since process start, capped by the
+//! `--semantic-baseline-window-days` flag (default 14 — but we don't
+//! persist across restarts in v1, so the window is effectively
+//! "uptime"). Per-resident persistent baselines arrive in v2 with the
+//! `SemanticState` log-replay path.
+//!
+//! Refractory: max 1 firing per 24 h to prevent alert spam.
+
+use std::time::Duration;
+
+use super::common::{PrimitiveConfig, PrimitiveState, RawSnapshot, Reason};
+
+const REFRACTORY: Duration = Duration::from_secs(24 * 3600);
+
+#[derive(Debug, Default, Clone)]
+pub struct ElderlyInactivityAnomaly {
+    pub active: bool,
+    idle_since: Option<Duration>,
+    /// Longest idle stretch observed so far. The "baseline" the multiplier
+    /// is applied against. Seeded to a sensible floor so the first day
+    /// doesn't fire spuriously.
+    longest_idle: Duration,
+    last_fire: Option<Duration>,
+}
+
+const BASELINE_FLOOR: Duration = Duration::from_secs(30 * 60); // 30 min
+
+impl ElderlyInactivityAnomaly {
+    pub fn new() -> Self {
+        Self { longest_idle: BASELINE_FLOOR, ..Default::default() }
+    }
+
+    pub fn tick(&mut self, snap: &RawSnapshot, cfg: &PrimitiveConfig) -> PrimitiveState {
+        if snap.since_start < cfg.warmup {
+            return PrimitiveState::Idle;
+        }
+        let still = snap.presence && snap.motion < 0.02;
+        if !still {
+            // Update baseline if we just emerged from a long stretch.
+            if let Some(start) = self.idle_since {
+                let dur = snap.since_start.saturating_sub(start);
+                if dur > self.longest_idle { self.longest_idle = dur; }
+            }
+            self.idle_since = None;
+            if self.active {
+                self.active = false;
+                return PrimitiveState::Boolean {
+                    active: false,
+                    changed: true,
+                    reason: Reason::new(&["motion_resumed"]),
+                };
+            }
+            return PrimitiveState::Idle;
+        }
+
+        let start = *self.idle_since.get_or_insert(snap.since_start);
+        let dur = snap.since_start.saturating_sub(start);
+        let threshold_secs = (self.longest_idle.as_secs_f64()) * cfg.elderly_anomaly_multiple;
+        let threshold = Duration::from_secs_f64(threshold_secs);
+
+        if !self.active && dur >= threshold {
+            // Refractory.
+            if let Some(t) = self.last_fire {
+                if snap.since_start.saturating_sub(t) < REFRACTORY {
+                    return PrimitiveState::Idle;
+                }
+            }
+            self.active = true;
+            self.last_fire = Some(snap.since_start);
+            return PrimitiveState::Boolean {
+                active: true,
+                changed: true,
+                reason: Reason::new(&[
+                    "presence=true",
+                    "motion<2%",
+                    "idle>2x_baseline",
+                ]),
+            };
+        }
+        PrimitiveState::Idle
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn cfg() -> PrimitiveConfig { PrimitiveConfig::default() }
+
+    fn still_snap(t_secs: u64) -> RawSnapshot {
+        RawSnapshot {
+            since_start: Duration::from_secs(t_secs),
+            presence: true,
+            motion: 0.01,
+            ..Default::default()
+        }
+    }
+
+    #[test]
+    fn fires_when_idle_exceeds_2x_baseline() {
+        let mut p = ElderlyInactivityAnomaly::new();
+        // baseline floor is 30 min → threshold = 60 min idle.
+        let _ = p.tick(&still_snap(100), &cfg());
+        let state = p.tick(&still_snap(100 + 61 * 60), &cfg());
+        match state {
+            PrimitiveState::Boolean { active, changed, .. } => {
+                assert!(active && changed);
+            }
+            other => panic!("expected on, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn does_not_fire_before_threshold() {
+        let mut p = ElderlyInactivityAnomaly::new();
+        let _ = p.tick(&still_snap(100), &cfg());
+        // 50 min idle, threshold is 60.
+        let state = p.tick(&still_snap(100 + 50 * 60), &cfg());
+        assert!(matches!(state, PrimitiveState::Idle));
+    }
+
+    #[test]
+    fn motion_clears_active_state() {
+        let mut p = ElderlyInactivityAnomaly::new();
+        let _ = p.tick(&still_snap(100), &cfg());
+        let _ = p.tick(&still_snap(100 + 61 * 60), &cfg());
+        assert!(p.active);
+        // Motion.
+        let mut s = still_snap(100 + 61 * 60 + 1);
+        s.motion = 0.10;
+        let state = p.tick(&s, &cfg());
+        match state {
+            PrimitiveState::Boolean { active, .. } => assert!(!active),
+            other => panic!("expected off, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn baseline_grows_to_observed_max() {
+        let mut p = ElderlyInactivityAnomaly::new();
+        // Establish a 90-min idle stretch — baseline should grow.
+        let _ = p.tick(&still_snap(100), &cfg());
+        let _ = p.tick(&still_snap(100 + 90 * 60), &cfg());
+        // p is now active. Force exit.
+        let mut s = still_snap(100 + 90 * 60 + 1);
+        s.motion = 0.20;
+        let _ = p.tick(&s, &cfg());
+        // Baseline updated.
+        assert!(p.longest_idle >= Duration::from_secs(89 * 60));
+    }
+
+    #[test]
+    fn refractory_prevents_repeat_alerts() {
+        let mut p = ElderlyInactivityAnomaly::new();
+        let _ = p.tick(&still_snap(100), &cfg());
+        let _ = p.tick(&still_snap(100 + 61 * 60), &cfg());
+        // Motion clears.
+        let mut s = still_snap(100 + 61 * 60 + 1);
+        s.motion = 0.20;
+        let _ = p.tick(&s, &cfg());
+        // 5 hours later, another 1h+ idle — should NOT fire (still <24h).
+        let _ = p.tick(&still_snap(100 + 5 * 3600), &cfg());
+        let state = p.tick(&still_snap(100 + 5 * 3600 + 70 * 60), &cfg());
+        assert!(matches!(state, PrimitiveState::Idle));
+    }
+}
diff --git a/v2/crates/wifi-densepose-sensing-server/src/semantic/fall_risk.rs b/v2/crates/wifi-densepose-sensing-server/src/semantic/fall_risk.rs
new file mode 100644
index 00000000..2de0f713
--- /dev/null
+++ b/v2/crates/wifi-densepose-sensing-server/src/semantic/fall_risk.rs
@@ -0,0 +1,214 @@
+//! Fall-risk-elevated primitive (§3.12.1 row 7).
+//!
+//! Continuous 0..100 score derived from gait instability + near-fall
+//! frequency over a rolling 24 h window. Emits a Scalar state every
+//! tick when active; emits a one-shot event when the score crosses
+//! `fall_risk_event_threshold` (default 70).
+//!
+//! v1 simplification: score = clamp(100, 10 * near_falls_24h +
+//! 50 * recent_motion_variance), where:
+//!   - near_falls_24h: count of `fall_detected` events in the trailing
+//!     24 h window (we don't expose near-falls separately in the
+//!     broadcast yet, so we approximate with confirmed falls)
+//!   - recent_motion_variance: variance of motion over the trailing
+//!     60 s.
+//!
+//! v2 will use the gait-instability score directly once it lands in
+//! the pose tracker (see ADR-027 §A4).
+
+use std::collections::VecDeque;
+use std::time::Duration;
+
+use super::common::{PrimitiveConfig, PrimitiveState, RawSnapshot, Reason};
+
+const RECENT_MOTION_WINDOW: Duration = Duration::from_secs(60);
+const FALL_HISTORY_WINDOW: Duration = Duration::from_secs(24 * 3600);
+
+#[derive(Debug, Default, Clone)]
+pub struct FallRiskElevated {
+    pub last_score: f64,
+    /// (timestamp, motion).
+    motion_history: VecDeque<(Duration, f64)>,
+    /// Timestamps of fall_detected=true events.
+    fall_history: VecDeque<Duration>,
+    /// True iff last emit was above the configured event threshold.
+    above_threshold: bool,
+}
+
+impl FallRiskElevated {
+    pub fn new() -> Self { Self::default() }
+
+    fn variance(samples: &VecDeque<(Duration, f64)>) -> f64 {
+        if samples.is_empty() { return 0.0; }
+        let mean = samples.iter().map(|(_, m)| m).sum::<f64>() / samples.len() as f64;
+        let v = samples
+            .iter()
+            .map(|(_, m)| (m - mean).powi(2))
+            .sum::<f64>()
+            / samples.len() as f64;
+        v
+    }
+
+    pub fn tick(&mut self, snap: &RawSnapshot, cfg: &PrimitiveConfig) -> PrimitiveState {
+        if snap.since_start < cfg.warmup {
+            return PrimitiveState::Idle;
+        }
+
+        // Maintain rolling motion history.
+        self.motion_history.push_back((snap.since_start, snap.motion));
+        while let Some(&(t, _)) = self.motion_history.front() {
+            if snap.since_start.saturating_sub(t) > RECENT_MOTION_WINDOW {
+                self.motion_history.pop_front();
+            } else {
+                break;
+            }
+        }
+
+        // Maintain rolling fall history.
+        if snap.fall_detected {
+            self.fall_history.push_back(snap.since_start);
+        }
+        while let Some(&t) = self.fall_history.front() {
+            if snap.since_start.saturating_sub(t) > FALL_HISTORY_WINDOW {
+                self.fall_history.pop_front();
+            } else {
+                break;
+            }
+        }
+
+        let near_falls = self.fall_history.len() as f64;
+        let var = Self::variance(&self.motion_history);
+        let score = (10.0 * near_falls + 50.0 * var).clamp(0.0, 100.0);
+        self.last_score = score;
+
+        // Event on crossing threshold upward.
+        let was_above = self.above_threshold;
+        self.above_threshold = score >= cfg.fall_risk_event_threshold;
+        if !was_above && self.above_threshold {
+            return PrimitiveState::Event {
+                event_type: "fall_risk_elevated",
+                reason: Reason::new(&["score>=70", "crossed_threshold"]),
+            };
+        }
+        PrimitiveState::Scalar {
+            value: score,
+            reason: Reason::new(&["score_published"]),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn cfg() -> PrimitiveConfig { PrimitiveConfig::default() }
+
+    #[test]
+    fn warmup_blocks_score() {
+        let mut p = FallRiskElevated::new();
+        let s = RawSnapshot {
+            since_start: Duration::from_secs(30),
+            motion: 0.5,
+            ..Default::default()
+        };
+        assert!(matches!(p.tick(&s, &cfg()), PrimitiveState::Idle));
+    }
+
+    #[test]
+    fn emits_scalar_when_active() {
+        let mut p = FallRiskElevated::new();
+        let s = RawSnapshot {
+            since_start: Duration::from_secs(120),
+            motion: 0.10,
+            ..Default::default()
+        };
+        let state = p.tick(&s, &cfg());
+        assert!(matches!(state, PrimitiveState::Scalar { .. }));
+    }
+
+    #[test]
+    fn score_grows_with_falls() {
+        let mut p = FallRiskElevated::new();
+        // Establish baseline with no falls.
+        let _ = p.tick(&RawSnapshot {
+            since_start: Duration::from_secs(120),
+            motion: 0.05,
+            ..Default::default()
+        }, &cfg());
+        let base_score = p.last_score;
+        // Add some falls.
+        for t in 121..125 {
+            let s = RawSnapshot {
+                since_start: Duration::from_secs(t),
+                motion: 0.05,
+                fall_detected: true,
+                ..Default::default()
+            };
+            let _ = p.tick(&s, &cfg());
+        }
+        // Score should be higher than baseline.
+        assert!(p.last_score > base_score);
+    }
+
+    #[test]
+    fn emits_event_when_crossing_threshold() {
+        let mut p = FallRiskElevated::new();
+        // Inject 7 falls → score ≥ 70.
+        let mut last_state = PrimitiveState::Idle;
+        for t in 120..127 {
+            let s = RawSnapshot {
+                since_start: Duration::from_secs(t),
+                motion: 0.05,
+                fall_detected: true,
+                ..Default::default()
+            };
+            last_state = p.tick(&s, &cfg());
+        }
+        // One of those ticks must have emitted the crossing event.
+        // Since we only catch the last call's return, check the score.
+        assert!(p.above_threshold, "should be above threshold");
+        // The crossing-event return is on the first tick that crosses.
+        // Verify the type via a fresh sequence.
+        let mut p2 = FallRiskElevated::new();
+        let _ = p2.tick(&RawSnapshot {
+            since_start: Duration::from_secs(120),
+            motion: 0.05,
+            ..Default::default()
+        }, &cfg());
+        let mut saw_event = false;
+        for t in 121..130 {
+            let s = RawSnapshot {
+                since_start: Duration::from_secs(t),
+                motion: 0.05,
+                fall_detected: true,
+                ..Default::default()
+            };
+            if matches!(p2.tick(&s, &cfg()), PrimitiveState::Event { .. }) {
+                saw_event = true;
+                break;
+            }
+        }
+        assert!(saw_event, "should have emitted crossing event");
+        // Suppress unused warning.
+        let _ = last_state;
+    }
+
+    #[test]
+    fn fall_history_evicts_after_24h() {
+        let mut p = FallRiskElevated::new();
+        // Inject fall.
+        let _ = p.tick(&RawSnapshot {
+            since_start: Duration::from_secs(120),
+            motion: 0.05,
+            fall_detected: true,
+            ..Default::default()
+        }, &cfg());
+        // 25 hours later — the fall should evict from the window.
+        let _ = p.tick(&RawSnapshot {
+            since_start: Duration::from_secs(120 + 25 * 3600),
+            motion: 0.05,
+            ..Default::default()
+        }, &cfg());
+        assert!(p.fall_history.is_empty(), "fall must evict after 24h");
+    }
+}
diff --git a/v2/crates/wifi-densepose-sensing-server/src/semantic/meeting.rs b/v2/crates/wifi-densepose-sensing-server/src/semantic/meeting.rs
new file mode 100644
index 00000000..fdb1273e
--- /dev/null
+++ b/v2/crates/wifi-densepose-sensing-server/src/semantic/meeting.rs
@@ -0,0 +1,141 @@
+//! Meeting-in-progress primitive (§3.12.1 row 5).
+//!
+//! Enter `meeting_in_progress = ON` when person_count ≥ 2 AND motion
+//! is sustained low-amplitude (people sitting still while talking) for
+//! ≥`meeting_dwell` (default 10 min).
+//!
+//! Exit when person_count < 2 for ≥2 min.
+
+use std::time::Duration;
+
+use super::common::{PrimitiveConfig, PrimitiveState, RawSnapshot, Reason};
+
+const EXIT_DWELL: Duration = Duration::from_secs(120);
+
+#[derive(Debug, Default, Clone)]
+pub struct MeetingInProgress {
+    pub active: bool,
+    enter_since: Option<Duration>,
+    exit_since: Option<Duration>,
+}
+
+impl MeetingInProgress {
+    pub fn new() -> Self { Self::default() }
+
+    pub fn tick(&mut self, snap: &RawSnapshot, cfg: &PrimitiveConfig) -> PrimitiveState {
+        if snap.since_start < cfg.warmup {
+            return PrimitiveState::Idle;
+        }
+        // Low-amplitude motion: people seated/quiet but present.
+        let suitable_motion = (0.01..0.20).contains(&snap.motion);
+        let enough_persons = snap.n_persons >= cfg.meeting_min_persons;
+
+        if !self.active {
+            if enough_persons && suitable_motion {
+                let start = *self.enter_since.get_or_insert(snap.since_start);
+                if snap.since_start.saturating_sub(start) >= cfg.meeting_dwell {
+                    self.active = true;
+                    self.exit_since = None;
+                    return PrimitiveState::Boolean {
+                        active: true,
+                        changed: true,
+                        reason: Reason::new(&[
+                            "n_persons>=2",
+                            "motion=1-20%",
+                            "dwell>=10min",
+                        ]),
+                    };
+                }
+            } else {
+                self.enter_since = None;
+            }
+            PrimitiveState::Idle
+        } else {
+            let too_few = snap.n_persons < cfg.meeting_min_persons;
+            if too_few {
+                let start = *self.exit_since.get_or_insert(snap.since_start);
+                if snap.since_start.saturating_sub(start) >= EXIT_DWELL {
+                    self.active = false;
+                    self.enter_since = None;
+                    self.exit_since = None;
+                    return PrimitiveState::Boolean {
+                        active: false,
+                        changed: true,
+                        reason: Reason::new(&["n_persons<2", "dwell>=2min"]),
+                    };
+                }
+            } else {
+                self.exit_since = None;
+            }
+            PrimitiveState::Idle
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn cfg() -> PrimitiveConfig { PrimitiveConfig::default() }
+
+    fn meeting_snap(t_secs: u64, n: u32) -> RawSnapshot {
+        RawSnapshot {
+            since_start: Duration::from_secs(t_secs),
+            presence: true,
+            motion: 0.05,
+            n_persons: n,
+            ..Default::default()
+        }
+    }
+
+    #[test]
+    fn fires_after_dwell_with_2_plus_people() {
+        let mut p = MeetingInProgress::new();
+        let _ = p.tick(&meeting_snap(100, 3), &cfg());
+        let state = p.tick(&meeting_snap(100 + 600, 3), &cfg());
+        match state {
+            PrimitiveState::Boolean { active, .. } => assert!(active),
+            other => panic!("expected on, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn does_not_fire_with_1_person() {
+        let mut p = MeetingInProgress::new();
+        for t in 100..(100 + 1200) {
+            assert!(matches!(p.tick(&meeting_snap(t, 1), &cfg()), PrimitiveState::Idle));
+        }
+        assert!(!p.active);
+    }
+
+    #[test]
+    fn does_not_fire_with_high_motion() {
+        let mut p = MeetingInProgress::new();
+        for t in 100..(100 + 1200) {
+            let mut s = meeting_snap(t, 3);
+            s.motion = 0.5;
+            assert!(matches!(p.tick(&s, &cfg()), PrimitiveState::Idle));
+        }
+        assert!(!p.active);
+    }
+
+    #[test]
+    fn exits_after_2_min_of_low_count() {
+        let mut p = MeetingInProgress::new();
+        let _ = p.tick(&meeting_snap(100, 3), &cfg());
+        let _ = p.tick(&meeting_snap(100 + 600, 3), &cfg());
+        assert!(p.active);
+        // Drop to 1 person.
+        let _ = p.tick(&meeting_snap(100 + 600 + 1, 1), &cfg());
+        // <2 min: still active.
+        let state = p.tick(&meeting_snap(100 + 600 + 60, 1), &cfg());
+        assert!(matches!(state, PrimitiveState::Idle));
+        assert!(p.active);
+        // Past 2 min: exit.
+        let state2 = p.tick(&meeting_snap(100 + 600 + 130, 1), &cfg());
+        match state2 {
+            PrimitiveState::Boolean { active, .. } => assert!(!active),
+            other => panic!("expected off, got {:?}", other),
+        }
+    }
+}
diff --git a/v2/crates/wifi-densepose-sensing-server/src/semantic/mod.rs b/v2/crates/wifi-densepose-sensing-server/src/semantic/mod.rs
index 9733cf96..685a387b 100644
--- a/v2/crates/wifi-densepose-sensing-server/src/semantic/mod.rs
+++ b/v2/crates/wifi-densepose-sensing-server/src/semantic/mod.rs
@@ -46,16 +46,18 @@
 //! Each module exports a struct implementing [`Primitive`] and a `new`
 //! constructor that takes a [`PrimitiveConfig`].
 
-// Primitives landing in P4.5a (this iteration):
 mod bathroom;
+mod bed_exit;
 mod bus;
 mod common;
+mod distress;
+mod elderly_anomaly;
+mod fall_risk;
+mod meeting;
+mod multi_room;
 mod no_movement;
 mod room_active;
 mod sleeping;
 
-// Primitives landing in P4.5b (next iteration): bed_exit, distress,
-// elderly_anomaly, fall_risk, meeting, multi_room.
-
 pub use bus::{SemanticBus, SemanticEvent, SemanticKind};
 pub use common::{PrimitiveConfig, PrimitiveState, RawSnapshot, Reason};
diff --git a/v2/crates/wifi-densepose-sensing-server/src/semantic/multi_room.rs b/v2/crates/wifi-densepose-sensing-server/src/semantic/multi_room.rs
new file mode 100644
index 00000000..23d1c538
--- /dev/null
+++ b/v2/crates/wifi-densepose-sensing-server/src/semantic/multi_room.rs
@@ -0,0 +1,138 @@
+//! Multi-room transition primitive (§3.12.1 row 10).
+//!
+//! Edge-triggered event: when an `active_zones` set changes such that
+//! one zone exited AND a different zone entered within
+//! `multi_room_gap` (default 10 s), fire `multi_room_transition` with
+//! the `from_zone` and `to_zone` baked into the reason tags.
+//!
+//! Useful for "who went from X to Y" automations (e.g. light the path,
+//! announce arrival in next room).
+
+use std::collections::HashSet;
+use std::time::Duration;
+
+use super::common::{PrimitiveConfig, PrimitiveState, RawSnapshot, Reason};
+
+#[derive(Debug, Default, Clone)]
+pub struct MultiRoomTransition {
+    last_zones: HashSet<String>,
+    last_exit: Option<(String, Duration)>,
+}
+
+impl MultiRoomTransition {
+    pub fn new() -> Self { Self::default() }
+
+    pub fn tick(&mut self, snap: &RawSnapshot, cfg: &PrimitiveConfig) -> PrimitiveState {
+        if snap.since_start < cfg.warmup {
+            self.last_zones = snap.active_zones.iter().cloned().collect();
+            return PrimitiveState::Idle;
+        }
+        let now: HashSet<String> = snap.active_zones.iter().cloned().collect();
+        let added: Vec<&String> = now.difference(&self.last_zones).collect();
+        let removed: Vec<&String> = self.last_zones.difference(&now).collect();
+
+        let mut result = PrimitiveState::Idle;
+
+        // Record the most recent exit.
+        if let Some(exited) = removed.first() {
+            self.last_exit = Some(((*exited).clone(), snap.since_start));
+        }
+
+        // Match exit with subsequent entry.
+        if let (Some(entered), Some((from_zone, exit_t))) = (added.first(), self.last_exit.as_ref()) {
+            let gap = snap.since_start.saturating_sub(*exit_t);
+            if gap <= cfg.multi_room_gap && from_zone.as_str() != entered.as_str() {
+                let reason = Reason::new(&[
+                    "zone_exit_to_entry",
+                    Box::leak(format!("from={}", from_zone).into_boxed_str()),
+                    Box::leak(format!("to={}", entered).into_boxed_str()),
+                ]);
+                result = PrimitiveState::Event {
+                    event_type: "multi_room_transition",
+                    reason,
+                };
+                // Consume the exit so we don't double-fire.
+                self.last_exit = None;
+            }
+        }
+
+        self.last_zones = now;
+        result
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn cfg() -> PrimitiveConfig { PrimitiveConfig::default() }
+
+    fn zones_snap(t_secs: u64, zones: &[&str]) -> RawSnapshot {
+        RawSnapshot {
+            since_start: Duration::from_secs(t_secs),
+            presence: !zones.is_empty(),
+            active_zones: zones.iter().map(|s| s.to_string()).collect(),
+            ..Default::default()
+        }
+    }
+
+    #[test]
+    fn fires_when_zone_changes_quickly() {
+        let mut p = MultiRoomTransition::new();
+        let _ = p.tick(&zones_snap(120, &["kitchen"]), &cfg());
+        // Exit kitchen.
+        let _ = p.tick(&zones_snap(125, &[]), &cfg());
+        // Enter living room within gap.
+        let state = p.tick(&zones_snap(128, &["living"]), &cfg());
+        match state {
+            PrimitiveState::Event { event_type, reason } => {
+                assert_eq!(event_type, "multi_room_transition");
+                assert!(reason.tags.iter().any(|t| t.contains("from=kitchen")));
+                assert!(reason.tags.iter().any(|t| t.contains("to=living")));
+            }
+            other => panic!("expected event, got {:?}", other),
+        }
+    }
+
+    #[test]
+    fn does_not_fire_after_long_gap() {
+        let mut p = MultiRoomTransition::new();
+        let _ = p.tick(&zones_snap(120, &["kitchen"]), &cfg());
+        let _ = p.tick(&zones_snap(125, &[]), &cfg());
+        // 15 s later — outside default 10 s gap.
+        let state = p.tick(&zones_snap(140, &["living"]), &cfg());
+        assert!(matches!(state, PrimitiveState::Idle));
+    }
+
+    #[test]
+    fn does_not_fire_on_same_zone_re_entry() {
+        let mut p = MultiRoomTransition::new();
+        let _ = p.tick(&zones_snap(120, &["kitchen"]), &cfg());
+        let _ = p.tick(&zones_snap(125, &[]), &cfg());
+        let state = p.tick(&zones_snap(128, &["kitchen"]), &cfg());
+        assert!(matches!(state, PrimitiveState::Idle));
+    }
+
+    #[test]
+    fn warmup_blocks_event() {
+        let mut p = MultiRoomTransition::new();
+        let _ = p.tick(&zones_snap(30, &["kitchen"]), &cfg());
+        let state = p.tick(&zones_snap(40, &["living"]), &cfg());
+        assert!(matches!(state, PrimitiveState::Idle));
+    }
+
+    #[test]
+    fn handles_simultaneous_zone_swap() {
+        // Some sensing scenarios emit exit + enter in the same tick.
+        let mut p = MultiRoomTransition::new();
+        let _ = p.tick(&zones_snap(120, &["kitchen"]), &cfg());
+        // Tick where kitchen left AND living entered simultaneously.
+        let state = p.tick(&zones_snap(123, &["living"]), &cfg());
+        match state {
+            PrimitiveState::Event { event_type, .. } => {
+                assert_eq!(event_type, "multi_room_transition");
+            }
+            other => panic!("expected event, got {:?}", other),
+        }
+    }
+}