Dean was very successful in keeping the face that he wanted to make under control. Eugh. Skanky, smug, fucking demons. He wanted to reach over and smack her but that wasn't a move that he had risked since pulling out of hell. Man, that had felt good. Just bitch-slappin' a demon.
He also managed not to just stare at Sam in disbelief. Send them back with what? The massive power of Sam's huge head? Dean had never seen his brother take on more than one demon and Dean, like a norma - like any other hunter, needed to have his demons trapped. Start spitting out the Latin, they could just leave their bodies and then where the hell would they be?
He'd tell you where. With a bunch of unconscious, if not dead, bodies and no answers.
Dean was all for being cocky and bluffing. However, he had not a single idea what Sam was up to and he would have liked to be clued in. He didn't dare show weakness or uncertainty in front of the demon, with it this close to him.
He just wished that Sam would just look at him and fill him in on some kind plan. Because Dean didn't dare just assume a certain action. He and Sam just didn't work in tangent, as in synch, as they used to. If it hadn't been obvious before, it certainly hit home now.