diff --git a/flags.cpp b/flags.cpp
index db39d1e7..3b9083b4 100644
--- a/flags.cpp
+++ b/flags.cpp
@@ -363,5 +363,9 @@ EX bool hornStuns(cell *c) {
     attackJustStuns(c, AF_NORMAL, moNone);
   }
 
+/** changing this wall for whatever reason may cause the game to crash */
+EX bool do_not_touch_this_wall(cell *c) {
+  return among(c->wall, waMirrorWall, waBarrier, waRoundTable);
+  }
 
 }
diff --git a/pcmove.cpp b/pcmove.cpp
index 0fc89e2e..ac3c139e 100644
--- a/pcmove.cpp
+++ b/pcmove.cpp
@@ -935,7 +935,7 @@ bool pcmove::attack() {
   }
 
 EX bool chaos_forbidden(cell *c) {
-  return among(c->wall, waMirrorWall, waBarrier, waRoundTable) || isMultitile(c->monst);
+  return do_not_touch_this_wall(c) || isMultitile(c->monst);
   }
 
 bool pcmove::perform_actual_move() {