A shooting game

i'm building a shooting game in which you need to shoot the creatures in order to score how many is possible and win the game.. i saw this code in several websites but i don't understand the "if" condition and why we need "removeChild" and "Splice" both??

The code:

function fl_EnterFrameHandler_5(event:Event):void

{

          notequals.start();

          //trace(dmutsArray.length);

          for (i = 0; i < dmutsArray.length; i++)

          {

                    if (MovieClip(dmutsArray).currentFrame == MovieClip(dmutsArray).totalFrames)

                    {

                              var obj:MovieClip = dmutsArray;

                              trace(MovieClip(obj.parent));

                              MovieClip(obj.parent).removeChild(obj);

                              dmutsArray.splice(dmutsArray.indexOf(obj), 1);

                              misses++;

                              txtMissed.text = "Missed: " + String(misses) + " / " + String((difficulty == 0) ? 20 : 10);

                              if ((difficulty == 0 && misses >= 20) || (difficulty == 1 && misses >= 10))

                              {

                                        notequals.removeEventListener(TimerEvent.TIMER,enterdmuiot);

                                        removeEventListener(Event.ENTER_FRAME, fl_EnterFrameHandler_5);

                                        gotoAndStop(3);

                              }

                              break;

                    }

          }

}

Thx:)