problem in simple script

[zhaniko93]

I was trying to make snow in flash, when problem appeared. Here's main .fla file AS:

import fl.controls.Slider;
import fl.controls.SliderDirection;
import fl.controls.CheckBox;


import bell;
var mc:MovieClip = new MovieClip();
addChild(mc);
var windVal:Number = 0;
var frq:Number = 1; 
var dados:Boolean = false;

stage.addEventListener(Event.ENTER_FRAME, snow);
wind_sldr.addEventListener(Event.CHANGE, wv);
herz.addEventListener(Event.CHANGE, ww);
cbb.addEventListener(MouseEvent.CLICK, cx);

function cx(e:MouseEvent)	{
	dados = cbb.selected;
	if(!dados)	{
		for(var p:Number = 0; p<mc.numChildren; p++)	{
			//if(Object(mc.getChildAt(p)).devs)	{
				Object(mc.getChildAt(p)).r();
				mc.removeChildAt(p);
			//}
			
		}
		
	}
	
}

function wv(e:Event)	{
windVal = wind_sldr.value;	
}

function ww(e:Event)	{
	frq = herz.value;
}


function snow(e:Event)	{
	for(var l:Number = 0; l<frq; l++)	{
	var m:bell = new bell();
	
	mc.addChild(m);
	}
	
	
}

And bell.as:

package {

	import flash.display.Sprite;
	import flash.display.MovieClip;
	import flash.events.Event;
	import fl.transitions.Tween;
	import fl.transitions.TweenEvent;
	import fl.transitions.easing.*;

	public class bell extends Sprite {

		public var spd:Number;
		public var ws:Number;
		public var wina:Number;
		public var devs:Boolean;

		public function bell() {
			addEventListener(Event.ADDED_TO_STAGE, added);
			addEventListener(Event.ENTER_FRAME, ef);

			this.graphics.beginFill(0xFFE9F7);
			this.graphics.drawCircle(0, 0, Math.random()*5);
			this.graphics.endFill();
		}

		public function added(e:Event) {
			this.x = Math.random() * MovieClip(root).stage.stageWidth;
			spd = 1 + Math.random() * 4;
		}


		public function ef(e:Event) {
			
			
			
			this.y += spd;
			if (MovieClip(root).windVal!=0) {
				if (MovieClip(root).windVal != wina) {
					ws = MovieClip(root).windVal - MovieClip(root).windVal/2 + Math.random()*MovieClip(root).windVal/2;
					wina = MovieClip(root).windVal;
				}
				this.x+=ws;

			}

			if (this.y >= MovieClip(root).stage.stageHeight) {
				removeEventListener(Event.ENTER_FRAME, ef);
				devs = true;
				if(!MovieClip(root).dados)	{
				MovieClip(root).mc.removeChild(this);
				}
				
			}
		}



		public function r()	{
			removeEventListener(Event.ENTER_FRAME, ef);
		}


	}

}

when cx() function is run, not every child of mc MovieClip is removed. Why?