In the news

I was listening to Origin Stories about nuclear war / arms race and they mentioned a number of near misses, wiki has a number:
https://en.wikipedia.org/wiki/List_of_nuclear_close_calls

This one in particular:

One of several vessels surrounded by American destroyers near Cuba, B-59 dove to avoid detection and was unable to communicate with Moscow for a number of days. USS Beale began dropping practice depth charges to signal B-59 to surface; however the captain of the Soviet submarine and its zampolit took these to be real depth charges.

With low batteries affecting the submarine's life support systems and unable to make contact with Moscow, the commander of B-59 feared that war had already begun and ordered the use of a 10-kiloton nuclear torpedo against the American fleet. The zampolit agreed, but the chief of staff of the flotilla (second in command of the flotilla) Vasily Arkhipov refused permission to launch. He convinced the captain to calm down, surface, and make contact with Moscow for new orders.

i.e. two out of the three people on an isolated sub needed to launch their nukes at America agreed to do so, only one withheld authorisation.