Telling Flash to Pause for a Period of Time then Play in Reverse

Hi! I have a Flash animation that, once it’s complete, I want it to freeze on that frame for a period of time (lets say 2 minutes), then I want the Flash animation to play backwards until it reaches the very beginning. Maybe pause again for a short time before playing again. In a sense, I want it to loop back and forth consistently.

I know how I could do this using the frames (basically copy and paste those frames and tell those frames to run in reverse, and make time between them simply by the number of frames between them). But I was specifically asked not to do it that way, and to use code instead. When I’ve tried to, it will either stop at the last frame or loop from the beginning again.

Thank you so much for your help! This site has been a savior to the Actionscript impaired.