A Heroes theory…

At the crucial moment, Nathan should grab whoever’s going to explode and fly off with him, thereby saving the city.

Think about it, he’s the guy with the seemingly useless power (so you’d never see it coming), and it would be a final redeeming act for a morally ambiguous (at best) character.

That’s my guess.

EDIT: Upon reflection, I suppose if it’s Peter that explodes, he could fly himself away (having absorbed Nathan’s power), but that’s much less dramatically satisfying.