For some reason this story reminded me of a character from The Hitchhiker's Guide to the Galaxy book and radio program called Fenchurch. She was a girl in a café who had a eureka revelation moment of how to change the world for the better. Unfortunately she is then obliterated along with the rest of Earth before she has the chance to tell anyone. Fortunately in the story there are multiple Earths and later Fenchurch is alive and well but without the knowledge her former self had attained.