It had not killed him; where is the flaw?

This daily create was submitted to here. I was tasked with creating an opening line of one of these twenty types. I decided to attempt the “pithy type”.

Before I could come up with an opening line it felt as if I had to know what the story itself would be about. So I began thinking about that. The only thing that could come to mind was the following aphorism by the famous mathematician G.H. Hardy:

If I could prove by logic that you would die in five minutes, I should be sorry you were going to die, but my sorrow would be very much mitigated by pleasure in the proof.

Spending so much time working on the problem here at summer science made me think of all the times I thought I had found a proof and in fact there was a massive flaw somewhere. So what if Hardy thought he had the proof, and maybe he was outwardly elated in front of the person who was supposed to die, what would happen when the other person didn’t die? That was the premise for the fictitious novel that this opening line belongs to.