var tntTime : float = 150;  
var tntObject : GameObject;
static var tntOrder : boolean = true;  
var pTNT : GameObject;
var rTNT : GameObject;

function Start()
{
pTNT.active = false;
rTNT.active = false;
}

function OnGUI () {  
if(tntOrder == true)
{
  GUI.Box (Rect (10,321,200,30), "TNT explodes through: " + tntTime);  
}
if (tntOrder)  
{  
  tntOrder = false; Timer();  
}  
}  

function Timer () {  
if (tntTime > 0) {  
yield WaitForSeconds (1F);  
tntTime --;  
tntOrder = true;  
}  
else {  
pTNT.active = true;
rTNT.active = true;
yield WaitForSeconds (1);  
Destroy(tntObject);
}  
}

using UnityEngine;
using System.Collections;

public class radiusTNT : MonoBehaviour {
     void OnTriggerEnter(Collider other) {
   if(other.tag == "radiusTNT")
   {
   Destroy(gameObject);
   }
     }
}