I just thought of another reason Juliet will die. Let's say that the bomb just teleports them all back to 2007. Juliet will be teleported into solid ground and be instantly killed. While there is an open crater where the Swan used to be, I don't think it was nearly deep enough to go all the way down to the bottom of that deep shaft she fell into. ... I didn't know about Elizabeth Mitchell being in "V". I guess that's why they're potentially writing her out?