Picture this happening about 30,000 times, and all at once.
That is, if not for a guy named Vasili Arkhipov.
According to Director of the National Security Archive Thomas Blanton and former Secretary of Defense Robert McNamara, a guy called Vasili Arkhipov "saved the world". The thing is, to launch a nuke, the top three Soviets on the B-59 needed a unanimous vote. Captain Savitsky and Political Officer Ivan Semonovich Maslennikov were all for it, but Arkhipov, a mere second-in-command, was not all that wild about wiping out human civilization.
The three got into an argument, and Arkhipov eventually persuaded the political officer that nuking the U.S. Navy was a bad idea, and that they should resurface instead (even if it meant, you know, death). Captain Savitsky was not happy with this, but since he did not have the votes to go nuclear, the submarine surfaced, and the crisis was averted. So yeah, find out where Vasili Arkhipov is buried right now, and send him a fruit basket large enough to be seen from freaking space. He may have been a communist, but you owe him your damned life.
Of course, after that terrifyingly close call the U.S. and Soviets realized we were all walking a tightrope above a pool of lava, and that we should make peace with one other before tripping into Armageddon. Ha! Nope: We kept the Cold War going for decades afterward and in fact came just as close to annihilation again thanks to a false alarm in the 1980s (the Soviets had false radar signals showing the U.S. had launched on them.) Yet another Soviet officer, Stanislav Petrov, would risk everything by standing down.