There's this concept in game theory that it's sometimes worth it to hurt yourself in order to hurt an uncooperative player. If you are always thinking "how do I minimize harm to myself" you get salamied to death. Same as in a poker game, you can't fold every time someone raises big, just because you don't know which times he actually has good cards. If you do he ends up with all your chips.
Other thing is about MAD. At some point this hypothesis needs to be tested. Yes, as a child of the cold war I am well aware of the stories about there being a warhead with my city's name in Cyrillic painted on it, and the same with every city in Russia, in English. We're conditioned to think that as soon as the missiles are launched, countermissiles will also launch, and then we're all doomed, planet is handed over to cockroaches.
I'm not sure it's true. For one, it's actually happened that missiles looked like they were in the air, and a Soviet guy decided it was best not to send missiles back, and we're all still here. I also get the feeling, from introspecting, that a lot of people would not actually press the button if they saw that radar picture. Would you make the world unlivable for little Russian kids? I'm not sure I would, and though I don't know how many people are making these decisions, my guess is it would be really freaking hard.
Which bring me to my next point, and this will cause some consternation. How bad is it if a nuke or two goes off? We care that the whole world isn't turned to dust, but if we get another Hiroshima somewhere, apart from the enormous shock it would cause, it might stand a reasonable chance of ending whatever conflict it happened in, just like the actual two nuclear attacks in Japan. Is that totally crazy, or is MAD literally coded into the machines now? Maybe someone can enlighten me.