Something seems very odd about this. I can't imagine a hoster that would allow a gun to discharge by somebody pulling on a belt. Even if it did I am pretty sure most holsters hold the gun handle up, which would have resulted in a bullet below the waist. Not sure, of course, but it seems the most likely explanation would be that it wasn't holstered, but simply shoved in his belt. Only other thing that would make sense would be if she was intentionally pulling it out of the holster. Otherwise I don't see how it is possible.