If you've got enough time and you're confident with manual exposure you could get some cactus radio triggers and use it off camera.

please tell me you looked up the voltages before you tried! other wise you are a brave man!
tip for using the flash at a club - use a longer exposure and have the flash fire right at the end of the exposure - the longer exposure captures the background lighting etc, and the flash freezes the subjects in the frame.
Definately have a practice before you do it though!