Kubrick: Dr. Strangelove or, How I Learned to Stop Worrying and Love the Bomb Act III
The question of Act I of Dr. Strangelove is "How could a thing like this happen?" The question of Act II is "Why would a thing like this happen?" and the question of Act III is "What if this happened?" The narrative takes us right up to the brink of unthinkability, then, rather incredibly, goes over it.