 The number 5 appears in the movie on several obvious occasions.  There are 5 elements. Zorg stops his bomb with 5 seconds remaining  on the timer and the Mangalores bomb starts with a 5 second timer.  Ruby Rhod, near the end of the movie after the alien planet is  stopped, says, "Theres a bomb going off every 5 minutes!" and the  doctor at the end says that Leeloo and Korben need 5 more minutes.  Also Ruby Rhods show is at 5.