The expression is interesting. It's almost as if he's making sure no one is watching them hug. He was all rigid when she first grabbed him, but then he relaxes into it and hold her back. And then he starts looking around, even though there's no one around. Is it proper for a General to go around hugging people? It's interesting for me (I love analysing Jack)that in the easier years he was quite tactile, but with responsibility, rank and such, he appears far more rigid and closed off. I think he secretly enjoyed someone reaching out to him for a change.