One time I was checking the gear on an ambulance parked in a small, closed garage. Someone had left the fire extinguisher laying on its side behind a gear bag, and the pin had fallen out (or was it sabotage...?!). I slid that bag around and it somehow engaged the extinguisher handle.

White powder was everywhere in about 1.2 seconds. It looked like a scene from "Scarface", but without the M16.