In 1962, the submarine B-59 was outside of Cuba when US destroyers dropped depth charges near it. Thankfully the cool head of the Flotilla Commander, Vasili Alexandrovich Arkhipov, was on and decided to contact Moscow to see if war was happening or not. Unknown to those warships the submarine carried a T-5 Nuclear Torpedo.
What if, Vaili had not been on that ship and the captain, thinking war was occurring launches the T-5 and sinks the US warships in a atomic cloud?