Yeah, Jack's close to all his team. But of his team, Carter's really the only one that he enforces a bit of a distance with -- there's the implication in Ascension that he's never been to her house before, there's her level of uncomfortableness when she's just dropping by his house in Lost City. The fact that, after four years of knowing her, neither Jack nor Daniel knew that she liked Diet Coke in Upgrades.

Do you think this is because she is the only one on his team that is military? He is bound by rules and regulations that he is not with Teal'c and Daniel. He is watching after her as much as protecting himself.