hitTest and set Interval

I have an interesting problem;

I have an initial movieclip (movieclip_1) loaded and I want to be able to time the length spent with the mouse down over movieclip_1 and then load movieclip_2 after, say, 10 seconds have elapsed.

If the mouse is pushed outside the active area then after the 10 seconds have elapsed, movieclip_3 is loaded instead.

Any ideas?

I would be very grateful.

My coding skills are abyssmal.