Open random mp3 in specified folder


See, its hard to explain but I've been trying to make an apple script code that opens a dialog box with a button that says "TWSS" and when you press it a random "thats what she said" mp3 (theres 16 separate clips) opens from a specified folder (with the mp3s in it).I'm trying to get it so that you can press it more than once without the dialog box closing. I've tried EVERYTHING but nothing will work, I'm only an amateur so I would really appreciate some help...