tutorial onClipEvent Question

[ksbigfoot]

I am trying to understand Collision detection from this code I downloaded. I have a player that moves through a maze.
The following code is placed on the maze movie clip.
I am wondering how to stop the player from moving after it hits the end movie clip when the user hits the arrow keys.

onClipEvent (enterFrame) {
	with (_root.player) {
		// Controls Player Speed
		mySpeed = 3;
		// Controls how far the Player bounces off the wall after impact 
		myBounce = 3;
		// keyboard controls
		if (Key.isDown(Key.DOWN)) {
				_y += mySpeed;
		}
		if (Key.isDown(Key.UP)) {
				_y -= mySpeed;
		}
		if (Key.isDown(Key.LEFT)) {
				_x -= mySpeed;
		}
		if (Key.isDown(Key.RIGHT)) {
				_x += mySpeed;
		}
		// detect if edges of the player is colliding with the Maze Walls 
		if (walls.hitTest(getBounds(_root).xMax, _y, true)) {
			_x -= myBounce;
		}
		if (walls.hitTest(getBounds(_root).xMin, _y, true)) {
			_x += myBounce;
		}
		if (walls.hitTest(_x, getBounds(_root).yMax, true)) {
			_y -= myBounce;
		}
		if (walls.hitTest(_x, getBounds(_root).yMin, true)) {
			_y += myBounce;
		}
		// detect if Maze is finished 
		if (_root.end.hitTest(_x, getBounds(_root).yMax, true)) {
			_root.gotoAndStop(3);
		}
	}
}