diff --git a/src/rooms/GeneralRoom.ts b/src/rooms/GeneralRoom.ts
index 3cd04d2..799abd0 100644
--- a/src/rooms/GeneralRoom.ts
+++ b/src/rooms/GeneralRoom.ts
@@ -128,6 +128,8 @@ export class GeneralRoom extends Room {
   }
 
   onDispose() {
+    this.gameClock.clear();
+    this.assistMap.clear();
     this.dispatcher.stop();
   }
 
@@ -268,8 +270,10 @@ export class GeneralRoom extends Room {
   }
 
   addAssistClient(sessionId: string) {
-    let client = new RobotClient(sessionId, this.state, this['onMessageHandlers']);
-    this.assistMap.set(sessionId, client);
+    if (!this.assistMap.has(sessionId)) {
+      let client = new RobotClient(sessionId, this.state, this['onMessageHandlers']);
+      this.assistMap.set(sessionId, client);
+    }
   }
 
   getAssistClient(sessionId: string): RobotClient {