I played in one of these as an "actor". It was used as practice for local first responders to a mass casualty event which would overwhelm their "normal" capacity. The simulated event was an airliner crash after touchdown, we were given makeup and cue cards to simulate various injuries. The first responders got to practice triage and trauma-type first aid. I personally think it's better if local EMS practices this shit, so if it goes down for real it won't be the first time they do it.