No military or civilian aircraft I have flown has clearly marked cut off switches and none of them has an intuitive system for closing them down
Saw a thread on another forum recently which included pcis of a C-124 Globemaster that had crashed and been destroyed while landing in Alaska in the 50s. However the port wing and u/c leg was still relatively intact and one of the engines (the inboard one I think) complete with prop continued running for quite a few hours afterwards. Can't remember whether it stopped through fuel exhaustion or if somebody found a way to stop it, but quite impressive. I believe all the crew survived OK by the way.