Perhaps saying something is the wrong choice entirely. There is little that you can say to work with PTSD that bad. He's been to enough therapists to know that rather well. What he can do, however, he does immediately. The man moves toward Rinoa, unbuttoning and shedding his coat as he goes. Panic attacks he can deal with. Soon he's on his knees next to Rinoa and 7, draping a coat over Rinoa's shoulders, and therefore 7's arm just a little bit. His hand rests on her shoulder through the coat.

"Tell me if that's too warm," he says, keeping his voice as low and soothing as he can. Which, actually, is a bit lower than his normal register, but for now, the goal is to calm the young woman. Without, of course, saying 'calm down'. That would be terrible in a situation like this. "For right now, I'd like you to focus on breathing, alright? Focus on the sound of the air sliding slowly in and out of your lungs. In, try to hold. Out, try to hold. Can you do that for me, miss?"

Meanwhile he looks to 7. Is there a way to quietly indicate that she should loosen her hug just a bit? If Rinoa needs to get up and move around she should absolutely be allowed to. After that memory of helplessness, of being unable to move herself, leaving her in a position where she couldn't move if she wanted to may be a poor choice. Unfortunately he cannot think of a tactful way to do so.

"What's your name, my dear?"