Random BGM

I've been working on a way to get a map to play a random background midi everytime you enter the map. here's the code:
Parallel process
chng variable rndm 1-5
frk option:[variable0001]
play bgm 1

end case:
clear timer
frk option:[variable002]
play bgm 2

end case
clear timer
etc...
The only problem with this is that the clear time operation stops the rest of the event, and the random selection is always on the first bgm.
What could I do to fix this?