fix floor switch error

src/scripts/floor_switch.gd

@@ -89,6 +89,10 @@ func _on_body_entered(body):
 
 func _on_body_exited(body):
 	# Object left the switch
+	# Check if node is still in scene tree (might be removed during level cleanup)
+	if not is_inside_tree():
+		return
+	
 	if body in objects_on_switch:
 		# For pillar switches, verify the object is still valid (not being held now)
 		if switch_type == "pillar":
@@ -99,7 +103,8 @@ func _on_body_exited(body):
 			if object_type == "Pillar":
 				var weight = _get_object_weight(body)
 				if weight > 0:
-					$ReleaseSwitch.play()
+					if is_inside_tree() and $ReleaseSwitch:
+						$ReleaseSwitch.play()
 					objects_on_switch.erase(body)
 					current_weight -= weight
 					print("FloorSwitch: Pillar left switch, weight: ", weight, ", total: ", current_weight)
@@ -108,7 +113,8 @@ func _on_body_exited(body):
 			# Walk switch: Remove any object
 			var weight = _get_object_weight(body)
 			if weight > 0:
-				$ReleaseSwitch.play()
+				if is_inside_tree() and $ReleaseSwitch:
+					$ReleaseSwitch.play()
 				objects_on_switch.erase(body)
 				current_weight -= weight
 				_check_activation()