Event - Freezes program when called

Hello, I'm making game where gameMenu Canvas should be displayed when I release Q button. For this I have created MenuToggle class which looks like:

 public class GameManager_MenuToggle : MonoBehaviour
     {
 
         public GameObject menuUI;
         public string menuButton;       
 
         private GameManager_Master gameManagerMaster;        
        
         private void OnEnable()
         {
             SetInitialReferences();
             gameManagerMaster.MenuToggleEvent += MenuToggle;
         }
 
         private void OnDisable()
         {
             gameManagerMaster.MenuToggleEvent -= MenuToggle;
         }
 
         void SetInitialReferences()
         {
             gameManagerMaster = GetComponent<GameManager_Master>();
         }
 
 
         private void Update()
         {
             CheckForMenuToggleRequest();
         }
 
         void CheckForMenuToggleRequest()
         {
             if (Input.GetKeyUp(KeyCode.Q))
             {
                 MenuToggle();
             }
         }
 
         void MenuToggle()
         {
             if (menuUI != null)
             {                
                 menuUI.SetActive(!menuUI.activeSelf);
                 Debug.Log("MenuToggle - change UI State");
                 gameManagerMaster.isMenuOn = !gameManagerMaster.isMenuOn;
                 gameManagerMaster.CallEventMenuToggle();
             }
         }
     }

As you can see I'm using GameManager_Master class which is like (I've cut stuff not relevent to this event):

 public class GameManager_Master : MonoBehaviour 
     {
 
         public delegate void GameManagerEventHandler();
         public event GameManagerEventHandler MenuToggleEvent;
        
      
         public bool isMenuOn;

      
         public void CallEventMenuToggle()
         {
             if (MenuToggleEvent != null)
             {
                 MenuToggleEvent();
             }
         }
 
         private void OnLevelWasLoaded(int level)
         {
             Time.timeScale = 1;
         }
 
     }

What is more when MenuToggleEvent is called my event system should trigger a Pause with script:

 public class GameManager_PauseToggle : MonoBehaviour
     {
         public GameObject playerController;
         private GameManager_Master gameManagerMaster;
         private bool isPaused;
 
         private void OnEnable()
         {
             SetInitialReferences();
             gameManagerMaster.MenuToggleEvent += PauseToggle;
             //gameManagerMaster.SpawnMenuToggleEvent += PauseToggle;
         }
 
         private void OnDisable()
         {
             gameManagerMaster.MenuToggleEvent -= PauseToggle;
             //gameManagerMaster.SpawnMenuToggleEvent -= PauseToggle;
         }
 
         void SetInitialReferences()
         {
             gameManagerMaster = GetComponent<GameManager_Master>();
         }
 
         void PauseToggle()
         {
             if (isPaused)
             {
                 Time.timeScale = 1;
                 isPaused = false;
                 playerController.GetComponent<FirstPersonController>().canRotate = true;
             }
             else
             {
                 Time.timeScale = 0;
                 isPaused = true;
                 playerController.GetComponent<FirstPersonController>().canRotate = false;
             }
         }
         
     }

All my stuff is in one single namespace called Simulator. I am using Unity v 5.6.0f3.