Five knew Allison would probably kill him for what he was about to do but Vanya deserved to know the truth. And he trusted her, despite knowing what she could do. It wasn't her fault, how could it be? She hadn't known she had powers, none of them had except their father. And he'd completely messed that up.
Five felt he owed her too; if he'd heeded her shake of the head before he'd disappeared he wouldn't have ran off and gotten stuck in the future. Sometimes he needed to pay more attention to others and the advice they offered, even if it was hard to admit. But for now he needed to focus on Vanya and not completely wrecking her when he told her what had happened. He only hoped he was doing the right thing.
Raising his hand he knocked on her door and waited.