void OnPlayerSpawn(GameObject player)
    {
        m_defenseActivator = player.GetComponentInChildren <DefenseActivator>();
        player.GetComponent <Destructible>().OnDeath += OnPlayerDeath;

        GameManager.Instance.NotifyPlayerSpawn -= OnPlayerSpawn;
    }
 private void OnPlayerDeath()
 {
     m_defenseActivator = null;
 }