Not that Meg was enthused about being in a place where there were more than one Winchester, but the demon would find a way to deal and survive - always did. Maybe the current meatsuit would come in handy, give for some blending and hopefully no one caught on. Meg always could be a good actor.
He'd knocked on the door and only waited a moment, mind going back to before he killed Bobby when Jo was tied up in the bar. She could've died then, could've. But Dean had to show up and spoil everything. Meg was almost glad to have not done that. Jo could prove to be helpful around the other Winchesters until he got back... "Hey."