Oh my. That was really, really powerful. I never would've thought of it---it's so simple, but it's so devastating. Hiro knows, in that moment, that the second he goes back to the future, everything could be completely different, and, just, GAH! The line "And neither of them would ever even know it" hits you like a punch in the gut. The thing is, though, it's such a Hiro thing to do---to help others, no matter what the cost. You've done an amazing job with this. I'm blown away.