Raycast collider detector lags horribly?

This script makes the game drop down from 30 fps to 3 fps. Here they seem to do it no problem(start at 1:00): Intruder Series 002 Concussion Grenades - YouTube

What is making the lag?

#pragma strict

var wake : boolean;

var power : float = 1000;
var damage : int = 1;
var radius : float = 3;

function Start () {

}

function Update () {
	if(wake == true) {
		Explode();
	}
}

function Explode() {
 
	var colliders : Collider[] = Physics.OverlapSphere (transform.position, radius);
	Debug.Log("Count of colliders = "+colliders.Length);
		for (var collider : Collider in colliders) {
			//if (collider.tag == "brick" || collider.tag == "player") {
				Debug.Log("Found brick or a player");
				var hit : RaycastHit;
				if (Physics.Linecast(transform.position, collider.transform.position, hit)) {
					if (hit.collider == collider) {
					Debug.Log("No obstructions");
						if (hit.rigidbody)
							hit.rigidbody.AddExplosionForce(power, transform.position, radius, 3.0);
				}
			}
		}
	//}
}

Debug.Log every frame will kill your framerate… That’s damn expensive as it walks the stack