diff --git a/src/server/api/api.ts b/src/server/api/api.ts
index ad6cb04..cdcd1d5 100644
--- a/src/server/api/api.ts
+++ b/src/server/api/api.ts
@@ -150,8 +150,9 @@ apiRouter.get("/get-ids", (_, res) => {
 
 apiRouter.get("/do-smth", async (_, res) => {
     const robotsEntries = Array.from(virtualRobots.entries());
+    const randomRobotIndex = Math.floor(Math.random() * robotsEntries.length)
     const [, robot] =
-        robotsEntries[Math.floor(Math.random() * robotsEntries.length)];
+        robotsEntries[randomRobotIndex];
     await robot.sendDrivePacket(1);
     await robot.sendTurnPacket(45 * DEGREE);
 
diff --git a/src/server/api/client-manager.ts b/src/server/api/client-manager.ts
index 536ce6b..32bbf99 100644
--- a/src/server/api/client-manager.ts
+++ b/src/server/api/client-manager.ts
@@ -60,7 +60,7 @@ export class ClientManager {
         }
     }
 
-    public getIds(): undefined | string[] {
+    public getIds(): undefined | [string, string] {
         if (this.hostId && this.clientId) {
             return [this.hostId, this.clientId];
         } else {
diff --git a/src/server/simulator.ts b/src/server/simulator.ts
index fe18222..67ef7ea 100644
--- a/src/server/simulator.ts
+++ b/src/server/simulator.ts
@@ -44,6 +44,9 @@ const parseErrorStack = (stack: string): StackFrame[] => {
             throw new Error(`Invalid stack frame: ${line}`);
         }
         const [, functionName, fileName, lineNumber, columnNumber] = match;
+        if (!functionName || !fileName || !lineNumber || !columnNumber) {
+            throw new Error(`Invalid stack frame: ${line}`);
+        }
         return {
             fileName,
             functionName,