Okay,so I have

public bool quitBool = false;

try 1

oid Update () {

 //if (Input.GetKeyUp(KeyCode.Escape))Application.Quit();

 if (Input.GetKeyDown(KeyCode.Escape) && quitBool == true){
     Application.Quit();
 }

 if (Input.GetKeyUp(KeyCode.Escape))quitBool = true;
     else quitBool = false;

}

try 2

if(Input.touchCount > 1)quitBool = false;

 if(Input.anyKey){
     if (Input.GetKeyUp(KeyCode.Escape))quitBool = true;
             else quitBool = false;
         }

 if (Input.GetKeyDown(KeyCode.Escape) && quitBool == true){
     Application.Quit();
 }

I can't seem to have it quit on doubletap. I tried having it quit on both GetKeyUp and GetKeyDown in both instances,then realised that the sequcence is key down->key up->key down->key up ,so i should be listening for the middle two,key down into key up right? But still doesn't seem to work,anyone got an idea of what is going on here?

Soultuon

okay,this seems to work

     if(Input.touchCount > 1)quitBool = false;

     if (Input.GetKeyDown(KeyCode.Escape) && quitBool == true){
         Application.Quit();
     }

     if(Input.anyKey){
             if (Input.GetKey(KeyCode.Escape))quitBool = true;
                 else quitBool = false;
     }

Hopefully someone finds it useful //thread :)