Here in S Florida a surprising number of ER personnel are armed. We know a bunch of them. And lots of doctors and lawyers and every other type of professional who are shooters. The local trauma hospital has a full time city police officer in the ER.
My wife once worked ER at Martin Luther King Hospital in Compton, California, ground zero for riots of the sixties and beyond (That's in Watts, for the geographically uninformed). There were lots of army surgeons getting combat training there in the late 1980's. It really was a war zone. They called it the "home boy ambulance service" when a car would come screeching up to the ER, dump out a gunshot victim, and speed off, tires squealing.