Vincent wasn't going let his guard down. He kept looking over his shoulders, lest Parvati ambush him. Having made it safely inside, he sat down near Pansy. Naturally, he didn't sit right next to her, but intended that spot for Draco.
He wondered what this meeting was all about. Did Dumbledore have a strategy for them? Would he remind them that they all had the right to exist? Vincent was still in knots over being marked for death. Even if Parvati intended to merely kill one or both of his parents, he wasn't so daft as to not realise that would mean he'd never be born. And of course, he knew he couldn't bear the death of yet another person he cared about.