// enemy 02 pattern
 // get call from Enemy_01_spawner
 void initiate_Event_C()
 {
     // path following enemy
     // this spawnEnemy will also call Enemy_5 formation follow the chain
     theEnemySpawner.spawnEnemy();
     //theEventDelegate -= initiate_Event_C;
 }
    IEnumerator Event_B()
    {
        float startTime = Time.time;          // current time
        float duration  = _event_B_duration;

        while (Time.time - startTime < duration)
        {
            yield return(new WaitForSeconds(Random.Range(max, min)));

            TopToDown();
        }

        Debug.Log("event B done");

        // start event C
        //EnemyEventManager.theEventDelegate ();
        MultipleEnemySpawner theEnemySpawner = GameObject.FindObjectOfType <MultipleEnemySpawner>();

        if (theEnemySpawner != null)
        {
            print("initiate event C");

            theEnemySpawner.spawnEnemy();
        }
    }