Random pattern for shoot em up enemy?

1

Hi all, im new to flash and im trying to make my first shoot 'em up game for fun. I wanted to make one kinda like a western style quick draw type thing. Everything works fine so far, but i was wondering how i can make my thug or “enemy” pop up in random positions in the saloon scene. Right now i just have his mc tweened to pop up behind the bar and his repeating pattern just sucks.