Stuck with this array

Question

so i have my code which makes the MC go to random places on the stage, but what i want is for the MC to go to each corner of the stage randomly, not all over the stage.
think its the arrays that need to be edited but im not sure?
any one have an answer?
import flash.events.MouseEvent;
addChild(btnPos1U);
btnPos1U.x=btnPos1U.y=0;
var positionA:Array=[[stage.stageWidth-btnPos1U.width,0],
                     [0,stage.stageHeight-btnPos1U.height],
                     [stage.stageWidth-btnPos1U.width,0],
                     [stage.stageWidth-btnPos1U.width,stage.stageHeight-btnPos1U.height]];
var t:Timer=new Timer(2000,0);
t.addEventListener(TimerEvent.TIMER,f);
t.start();
function f(e:TimerEvent):void{
btnPos1U.visible = true
btnPos1U.x=Math.floor(Math.random()*(stage.stageWidth-btnPos1U.width))
btnPos1U.y=Math.floor(Math.random()*(stage.stageHeight-btnPos1U.height))
btnPos1U.addEventListener(MouseEvent.CLICK,g)
function g (e:MouseEvent):void
    btnPos1U.visible = false
    init();
    btnNeg1.addEventListener(MouseEvent.CLICK, EndUnlimited);
    btnNeg2.addEventListener(MouseEvent.CLICK, EndUnlimited);
    btnNeg3.addEventListener(MouseEvent.CLICK, EndUnlimited);
    btnNeg4.addEventListener(MouseEvent.CLICK, EndUnlimited);
    btnPos1U.addEventListener(MouseEvent.CLICK, on_press);
function EndUnlimited (e:MouseEvent):void
    gotoAndPlay(102);
stop();

Answer 1

There is no "MC" in your code.  If you are talking about the button that gets randomly placed, that happens in the following two lines:
btnPos1U.x=Math.floor(Math.random()*(stage.stageWidth-btnPos1U.width))
btnPos1U.y=Math.floor(Math.random()*(stage.stageHeight-btnPos1U.height ))
The array you speak of identifies the locations of the four corners of the stage, which is what you want to pick from I would guess.  Think thru what you have and what you want and figure out how to make use of what you have to get there.