Ah... so since Voldemort shares Harry's blood then wasn't Harry perfectly safe in the last duel? If Voldemort managed to land a spell on him (ignoring the Elder Wand) then he'd still live yea? I don't recall any explanation towards why accepting death would allow him to return; Dumbledore just says that's how it is.

The problem is that with that logic, Voldemort shouldn't have died either since he has the same blood... so I guess he was just sent to that white dreamy area and couldn't go back because he wasn't expecting to die.