private void Update()
    {
        // checks based on how many enemies defeated
        if (isBeatByLeavingTrigger == false)
        {
            _objectiveCompleted = true;
            for (int i = 0; i < enemies.Count; i++)
            {
                if (enemies[i] != null)
                {
                    _objectiveCompleted = false;
                    break;
                }
            }

            if (_objectiveCompleted == true)
            {
                for (int i = 0; i < exitDoors.Count; i++)
                {
                    if (exitDoors[i])
                    {
                        exitDoors[i].SetActive(false);
                    }
                }
            }

            if (_objectiveCompleted && isFinalObjective)
            {
                _gameFlowManager.SetLevelComplete(true);
            }
        }
    }