Well, the battery compartment on one of my friends guns was opening all the time also. We couldn't figure out what was wrong with it.
That must have been weird, 3.......2........1.......GO, You jump off the line and slide into the carwash on the left tape. You crawl forward and snap shoot at the guy across the field. You get 2 shots, and realize that your hopper is lying behind you with the batterys on the ground.