diff --git a/src/simulator/crates/mc-turn/tests/event_collector_wiring.rs b/src/simulator/crates/mc-turn/tests/event_collector_wiring.rs
index 472b7c4f..3b4754ff 100644
--- a/src/simulator/crates/mc-turn/tests/event_collector_wiring.rs
+++ b/src/simulator/crates/mc-turn/tests/event_collector_wiring.rs
@@ -94,8 +94,11 @@ fn fixture_state() -> GameState {
     p0_city0.queue_tier = Some(1);
     p0_city0.production_stored = 5_000;
 
-    // Stand 3 player-0 units on player-1's only city tile so the siege
-    // capture trigger (`nearby_attackers >= 3`) fires immediately.
+    // Stand 3 player-0 units on player-1's only city tile so the per-unit
+    // HP-gated siege in `process_siege` captures it. A starter city has 510 hp
+    // and siege deals 15/attacker/turn; drop the defender city below the
+    // single-turn 3-attacker total (45) so CityCaptured fires on turn 1.
+    state.players[1].cities[0].hp = 30;
     let p1_city_pos = state.players[1].city_positions[0];
     for i in 0..3 {
         state.players[0].units.push(MapUnit {
diff --git a/src/simulator/crates/mc-turn/tests/last_survivor_via_capture.rs b/src/simulator/crates/mc-turn/tests/last_survivor_via_capture.rs
index 84bbb7a8..20501fc6 100644
--- a/src/simulator/crates/mc-turn/tests/last_survivor_via_capture.rs
+++ b/src/simulator/crates/mc-turn/tests/last_survivor_via_capture.rs
@@ -8,9 +8,9 @@
 //! && `cities.is_empty()`) stayed false forever and domination /
 //! last-survivor never fired even after total annihilation.
 //!
-//! This test exercises the actual capture pipeline (3 attacker units
-//! within 2 hexes of the defender's only city → `nearby_attackers >= 3`
-//! → `process_siege` swap-removes the city), then asserts both:
+//! This test exercises the actual capture pipeline (3 attacker units on the
+//! defender's only city tile → the per-unit HP-gated siege in `process_siege`
+//! drives the city's hp to 0 → the city is swap-removed), then asserts both:
 //!   • `defender.capital_position == None` after capture
 //!   • `TurnEvent::GameOver { reason_kind: "last_survivor", winner: 0 }`
 //!     emitted.
@@ -78,11 +78,15 @@ fn capturing_last_city_clears_capital_and_emits_last_survivor() {
     let p1_pos = (8, 0);
 
     let mut p0 = player_with_city_at(0, p0_pos);
-    let p1 = player_with_city_at(1, p1_pos);
+    let mut p1 = player_with_city_at(1, p1_pos);
+    // HP-gated siege deals 15 dmg per attacker per turn (`process_siege`); a
+    // starter city has 510 hp. Drop the defender's lone city below the
+    // single-turn 3-attacker siege total (3 × 15 = 45) so the capture completes
+    // on the first step, as this Bug-5 regression requires.
+    p1.cities[0].hp = 30;
 
-    // Stack 3 p0 units on p1's only city → siege capture trigger fires
-    // (matches the `nearby_attackers >= 3` predicate in
-    // `processor::process_siege`).
+    // Stack 3 p0 units on p1's only city tile → the per-unit siege loop in
+    // `processor::process_siege` drives the city's hp to 0 and captures it.
     for i in 0..3 {
         p0.units.push(MapUnit {
             id: 100 + i,