I think between that and next week, the future has definitely been changed. Remember, when past Hiro showed up 5 years later, future Hiro said "You saved the cheerleader, but the bomb still went off" meaning something else still needed to be done, but since Hiro skipped past it, it still happened. Of course, part of that "something else" is killing Sylar. So maybe Sylar does attempt to nuke the city and Hiro stops him.

Originally posted by: Johnny Ringo
Peter died - they didn't know Claire would / could resurrect him

I don't think Claire did resurrect him. Sure, she pulled the glass out of his head, but he had already absorbed her power before. If I'm not mistaken, he only needs to absorb the power once in order to use it again. At least that's the way it appears. He survived the fall by thinking about Claire. He made himself invisible without the other guy being around. Maybe it's a combination of sorts. Perhaps when someone is nearby, he just naturally absorbs and uses their power, but if they're not around, he has to think about them in order for that to work.

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