Anna was well aware that she had no power to calm Mary or Johnny or anyone else in the room besides, perhaps, Castiel. She put her gun away and her hand found his. She wanted answers more than she wanted to take on a potentially losing battle.
She looked over at him to gauge his reaction to all of this. She did not expect nor want him to blindly follow her lead, but she thought that they might be on the same page on this.
Once she had Castiel's hand, she started to move toward the seats to sit. She could only hope that the others followed suit.