So Zatanna was there. And from the sounds of it, she knew who Dinah was. Even though the situation was tense, she felt a little bit lighter with the knowledge that someone whom she considered a friend was here and actually knew her.
But there wasn't time to think about that. Right now, she had to keep things from getting uglier. She gave John a frustrated look because he really could have been a little bit nicer and still set the same terms.
And then she turned to Dean and put a hand on his arm, leaning in closely so she could speak to just him. The hold on his arm was firm without being overly aggressive. The message was hopefully there all the same.
She was on his side and she would do what she could to help him, but if he tried to make a fight of it she would intervene. She had fought opponents that were larger than he was and managed to lay them out flat even without her cry. If she had to do that to keep him from tangling with John and possibly Zee, she would.
"It would be good for you to trust me just this once," she said in a voice low enough that only Dean would be able to hear. "Whatever they're doing in there, if you make a fight out of it it could throw off some magic and possibly kill us all. Sam included. Zatanna is more reasonable than John so I'll go and talk to her and negotiate terms for you to get in there to see how Sam's doing."
She didn't let go, but instead waited for Dean's reaction.