Castro only had Cuba to lose, which is why he didnt mind. Khruschev had far more to lose, which is why to him the war was unthinkable.

Well Castro also seemed quite ready to die for a cause, what if kruschev had been a young and aggresively minded like fidel, if your going to die the size of your empire seems unimportant, or simply because fidel thought the war was winnable, and some people did....

Im not saying it's likely but you cannot rule it out as a possibility....