I haven't seen a convincing closure of the debate about whether Petrov was actually the only serious obstacle to WWIII. Obviously he did the right thing, I'm not trying to take that away from him, but I'd be very interested in hearing a more thorough analysis of what would have happened if he had reported up the chain of command that the computer said the US had launched ONE (EDIT: LATER 5) missile(s) but that since one missile launch was a pretty stupid thing to do, it was probably an error.