User blog comment:27finnsprincess/Finn may be the Tragedy/@comment-5430344-20121022235654/@comment-12.170.95.4-20121023000005

Except we're forgetting that by the time of the nuclear war, humanity was at least somewhat more advanced than today - holographic tech, lasers, and other thing's we've seen. Its entire possible that Finn gets his robot arm in the past.