C# Infinite loop or Unity Glich

Hello. This code kills unity at runtime. The Unity irc says it is a glich in unity, but I’m not so sure. Thanks.

P.S. If it makes and difference, I am running Win 7 x64

Here is the code, it is based of Unity’s Instantiation example.

using UnityEngine;
using System.Collections;

public class LevalManager : MonoBehaviour {
	
	public int layers;
	
	private EditorGUI REditorGUI;
	
	void Start () {
		REditorGUI = GetComponent<EditorGUI>();
		if (layers <= 0) {
			layers = 1;
		}
		
		for (int y = 0; y < layers; y++) {	
			for (int z = 0; y < layers; z++) {
				for (int x = 0; x < layers; x++){
					GameObject cube = GameObject.CreatePrimitive(PrimitiveType.Cube);
					cube.transform.position = new Vector3(x, y, z);
				}	
			}
		}	
	}
	
	void Update () {
		if(Input.GetMouseButton(0) && REditorGUI.bMouseOverGUI == false) {
			}
				
		}
	}

Oops, My bad, I had a code error causing a infinite loop. for (int z = 0; y < layers; z++)