diff --git a/source/cell.c b/source/cell.c
index d8f36e23..4fc6050e 100644
--- a/source/cell.c
+++ b/source/cell.c
@@ -456,7 +456,7 @@ int cell_init(int argc, char **argv)
   if (scheduler_actor_count() > 0) {
     actor_loop();
     exit_handler();
-    return exit_code;
+    exit(0);
   }
 
   /* No actors spawned — clean up CLI context */
diff --git a/source/mach.c b/source/mach.c
index 606c1afc..3b6436ce 100644
--- a/source/mach.c
+++ b/source/mach.c
@@ -2552,7 +2552,7 @@ static JSValue reg_vm_binop(JSContext *ctx, int op, JSValue a, JSValue b) {
   }
 
   /* Type mismatch — disrupt */
-  return JS_EXCEPTION;
+  return JS_ThrowTypeError(ctx, "type mismatch in binary operation");
 }
 
 /* Check for interrupt */
@@ -3021,6 +3021,8 @@ JSValue JS_CallRegisterVM(JSContext *ctx, JSCodeRegister *code,
       JSValue func_val = frame->slots[base];
 
       if (!JS_IsFunction(func_val)) {
+        JS_ThrowTypeError(ctx, "not a function");
+        frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
         goto disrupt;
       }
 
@@ -3263,7 +3265,11 @@ JSValue JS_CallRegisterVM(JSContext *ctx, JSCodeRegister *code,
       /* push R(B) onto array R(A) */
       JSValue arr = frame->slots[a];
       JSValue val = frame->slots[b];
-      if (!JS_IsArray(arr)) goto disrupt;
+      if (!JS_IsArray(arr)) {
+        JS_ThrowTypeError(ctx, "cannot push to non-array");
+        frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
+        goto disrupt;
+      }
       JSGCRef arr_gc;
       JS_PushGCRef(ctx, &arr_gc);
       arr_gc.val = arr;
@@ -3278,7 +3284,11 @@ JSValue JS_CallRegisterVM(JSContext *ctx, JSCodeRegister *code,
     case MACH_POP: {
       /* R(A) = pop last element from array R(B) */
       JSValue arr = frame->slots[b];
-      if (!JS_IsArray(arr)) goto disrupt;
+      if (!JS_IsArray(arr)) {
+        JS_ThrowTypeError(ctx, "cannot pop from non-array");
+        frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
+        goto disrupt;
+      }
       JSValue val = JS_ArrayPop(ctx, arr);
       frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
       if (JS_IsException(val)) goto disrupt;
@@ -3353,7 +3363,13 @@ JSValue JS_CallRegisterVM(JSContext *ctx, JSCodeRegister *code,
           break;
         }
         if (JS_IsNull(frame->caller)) {
-          fprintf(stderr, "unhandled disruption\n");
+          if (!JS_HasException(ctx)) {
+            /* Bare disrupt with no error message — provide location */
+            const char *fn_name = code->name_cstr ? code->name_cstr : "<anonymous>";
+            fprintf(stderr, "unhandled disruption in %s\n", fn_name);
+          } else {
+            fprintf(stderr, "unhandled disruption\n");
+          }
           result = JS_Throw(ctx, JS_NULL);
           frame = (JSFrameRegister *)JS_VALUE_GET_PTR(frame_ref.val);
           goto done;
diff --git a/source/scheduler.c b/source/scheduler.c
index df0ed40e..ad566855 100644
--- a/source/scheduler.c
+++ b/source/scheduler.c
@@ -304,6 +304,7 @@ void actor_free(cell_rt *actor)
 
   int actor_count = lockless_shlen(actors);
   if (actor_count == 0) {
+    fprintf(stderr, "all actors are dead\n");
     pthread_mutex_lock(&engine.lock);
     engine.shutting_down = 1;
     pthread_cond_broadcast(&engine.wake_cond);
@@ -533,7 +534,7 @@ const char *register_actor(const char *id, cell_rt *actor, int mainthread, doubl
   actor->main_thread_only = mainthread;
   actor->id = strdup(id);
   actor->ar_secs = ar;
-  int added = lockless_shput_unique(actors, id, actor);
+  int added = lockless_shput_unique(actors, actor->id, actor);
   if (!added) {
     free(actor->id);
     return "Actor with given ID already exists.";
@@ -591,20 +592,22 @@ void actor_turn(cell_rt *actor)
   arrdel(actor->letters, 0); // O(N) but we kept array as requested
   pthread_mutex_unlock(actor->msg_mutex);
   
-  if (l.type == LETTER_BLOB) { 
+  if (l.type == LETTER_BLOB) {
     // Create a JS blob from the C blob
     size_t size = blob_length(l.blob_data) / 8; // Convert bits to bytes
     JSValue arg = js_new_blob_stoned_copy(actor->context, (void*)blob_data(l.blob_data), size);
     blob_destroy(l.blob_data);
     result = JS_Call(actor->context, actor->message_handle_ref.val, JS_NULL, 1, &arg);
-    uncaught_exception(actor->context, result);
+    if (!uncaught_exception(actor->context, result))
+      actor->disrupt = 1;
     JS_FreeValue(actor->context, arg);
   } else if (l.type == LETTER_CALLBACK) {
     result = JS_Call(actor->context, l.callback, JS_NULL, 0, NULL);
-    uncaught_exception(actor->context, result);
+    if (!uncaught_exception(actor->context, result))
+      actor->disrupt = 1;
     JS_FreeValue(actor->context, l.callback);
   }
-  
+
   if (actor->disrupt) goto ENDTURN;
 
   ENDTURN:
@@ -612,9 +615,17 @@ void actor_turn(cell_rt *actor)
 
   if (actor->trace_hook)
     actor->trace_hook(actor->name, CELL_HOOK_EXIT);
-  
+
+  if (actor->disrupt) {
+    /* Actor must die. Unlock before freeing so actor_free can
+       lock/unlock/destroy the mutex without use-after-free. */
+    pthread_mutex_unlock(actor->mutex);
+    actor_free(actor);
+    return;
+  }
+
   set_actor_state(actor);
-  
+
   pthread_mutex_unlock(actor->mutex);
 }