Playing random movieClips onClick, then returning to start screen

Question

Hi- I'm very new to actionScript 3. My project starts out by plying one movie clip(startPage), then onClick, moviecip startPage disappears and a random movieclip(sc01-sc03) loads and plays. Once each random movieclip plays, I want to remove it from the stage and reload startPage. I have the random part figured out using an array, but I can't figure out how to remove the random sc movieClip once it is loaded. I tried using removeChild, but Flash isn't recognizing that I have added and of the sc movieclips as childen. Help!
My current code below:
package
          import flash.display.MovieClip;
          import flash.events.MouseEvent;
          import flash.events.Event;
          public class Main extends MovieClip
                    var startPage:StartPage;
                    var sc01:Sc01;
                    var sc02:Sc02;
                    var sc03:Sc03;
                    private var _scenario:Array;
                    public function Main()
                              startPage = new StartPage();
                              sc01 = new Sc01();
                              sc02 = new Sc02();
                              sc03 = new Sc03();
                              _scenario = new Array();
                              MC.addChild(startPage);
                              //Add Scenes to array
                              _scenario[0] = sc01;
                              _scenario[1] = sc02;
                              _scenario[2] = sc03;
                              //Add Event Listeners
                              startPage.boxButton.addEventListener(MouseEvent.CLICK,onBoxButtonClick);
                              startPage.addFrameScript(startPage.totalFrames - 1, stopPageFunc);
                              sc01.addEventListener(Event.ENTER_FRAME, everyFrame01);
                              sc02.addEventListener(Event.ENTER_FRAME, everyFrame02);
                              sc03.addEventListener(Event.ENTER_FRAME, everyFrame03);
                              //stop at end of startPage timeline
                              function stopPageFunc()
                                            startPage.stop();
                              function onBoxButtonClick(event:MouseEvent):void
                                        MC.removeChild(startPage);
                                        MC.addChild(_scenario[Math.floor(Math.random()*_scenario.length)]);
                              function everyFrame01():void
                                        if (sc01.currentFrame == 50)
                                        MC.removeChild(sc01);
                                        MC.addChild(startPage);
                                        startPage.gotoAndPlay(1);
                                        else
                                        {sc01.play();
                              function everyFrame02():void
                                        if (sc02.currentFrame == 50)
                                        MC.removeChild(sc02);
                                        MC.addChild(startPage);
                                        startPage.gotoAndPlay(1);
                                        else
                                        {sc02.play();
                              function everyFrame03():void
                                        if (sc03.currentFrame == 50)
                                        MC.removeChild(sc03);
                                        MC.addChild(startPage);
                                        startPage.gotoAndPlay(1);
                                        else
                                        {sc03.play();
                    //go to startPage when scenario done

Answer 1

use:
package
          import flash.display.MovieClip;
          import flash.events.MouseEvent;
          import flash.events.Event;
          public class Main extends MovieClip
                    var startPage:StartPage;
                    private var _scenario:Array;
                    public function Main()
                              startPage = new StartPage();
                              _scenario = new Array();
                              MC.addChild(startPage);
                              //Add Scenes to array
                              _scenario[0] = new Sc01();
                              _scenario[1] = new Sc02();
                              _scenario[2] = new Sc03();
shuffle(_scenario);
                              //Add Event Listeners
                              startPage.boxButton.addEventListener(MouseEvent.CLICK, onBoxButtonClick);
                              startPage.addFrameScript(startPage.totalFrames - 1, stopPageFunc);
                              this.addEventListener(Event.ENTER_FRAME, everyFrame;
                              //stop at end of startPage timeline
                              function stopPageFunc()
                                            startPage.stop();
                              function onBoxButtonClick(event:MouseEvent):void
if(startPage.stage){
                                        MC.removeChild(startPage);
if(_scenario.length>0){
                                        MC.addChild(_scenario[0]);
                              function everyFrame():void
if(_scenario[0].currentFrame==_scenario[0].totalFrames){
MC.removeChild(_scenario[0]);
_scenario.shift();
if(_scenario.length==0){
// startPage.gotoAndPlay(1); ???
MC.addChild(startPage);
function shuffle(a:Array) {
    var i:int;
    var j:int;
    var e:*;
    var len:int = a.length;
    for (i = len-1; i>=0; i--) {
        j=Math.floor((i+1)*Math.random());
        e = a[i];
        a[i] = a[j];
        a[j] = e;