diff --git a/src/creep-tasks/prototypes.ts b/src/creep-tasks/prototypes.ts
index b12592e..59e2242 100644
--- a/src/creep-tasks/prototypes.ts
+++ b/src/creep-tasks/prototypes.ts
@@ -104,7 +104,9 @@ Object.defineProperty(RoomPosition.prototype, 'neighbors', {
 
 RoomPosition.prototype.isPassible = function (ignoreCreeps = false): boolean {
 	// Is terrain passable?
-	if (Game.map.getTerrainAt(this) == 'wall') return false;
+  if (Game.map.getRoomTerrain(this.roomName).get(this.x, this.y) == TERRAIN_MASK_WALL) {
+    return false;
+  }
 	if (this.isVisible) {
 		// Are there creeps?
 		if (ignoreCreeps == false && this.lookFor(LOOK_CREEPS).length > 0) return false;