diff --git a/src/simulator/crates/mc-turn/src/processor.rs b/src/simulator/crates/mc-turn/src/processor.rs
index bb6d5ce9..60e2e734 100644
--- a/src/simulator/crates/mc-turn/src/processor.rs
+++ b/src/simulator/crates/mc-turn/src/processor.rs
@@ -1349,7 +1349,8 @@ impl TurnProcessor {
 
         // Remove killed units in reverse order per player to keep indices valid.
         // Credit strategic resources back to the owning player on death.
-        let mut kills_by_player: HashMap<usize, Vec<usize>> = HashMap::new();
+        // BTreeMap ensures players are processed in deterministic index order.
+        let mut kills_by_player: std::collections::BTreeMap<usize, Vec<usize>> = std::collections::BTreeMap::new();
         for &(pi, ui) in &killed {
             kills_by_player.entry(pi).or_default().push(ui);
         }