The craziest thing I ever saw on the subways as an EMT was the Union Square accident 20 years ago. An inebriated train operator took a switch just north of the station at several times the posted speed. The train derailed and killed five people. We treated and transported around 200 other patients to hospitals all over Manhattan. I was just getting ready to go home (it was around 1 AM, IIRC, I was doing tour 3, a 1800 x 0200) when we got banged with this call as a "late job". I remember it was hotter than bloody hell down there, and that we carried this hugely fat woman up a frighteningly narrow stairway from the Brooklyn-bound plat.
The real kicker is, the T/O got down from his cab after the wreck, walked up to Union Square Park, sat down on a bench, and drank beer as he watched all the crews take the patients away from the station. He was later sent to prison for five years--a relatively lenient sentence, considering.