He probably had it tucked into his pants homie style, instead of using a holster. Also, only the cheapo guns fire when dropped. Good guns, even simple revolvers, have internal safety devices to prevent this happening.
Ahhh..........cheapo guns.
Many years ago, on a whim, I bought a Raven .25; of course, I never carried in my waistband. Never carried it all, it just sat in my desk drawer.
I always figured if push came to shove, I could throw it at someone.