Although, to clarify, I do think there's at least regret about what he did and some sense of ... I don't know what I want to call it, although not exactly shame. I think it's telling that "what if it was your mother, would you still?" is the question that finally breaks Carroll down in the ethics seminar and that the breakdown happens after Carroll's already answered that yes, he would still. I think that parallels what Rodney did to Atlantis, and I wonder if Carroll's intense physical reaction isn't supposed to give us some insight into how Rodney feels about what he did. He may feel it was the right decision, or the better decision, but that doesn't mean there's no psychological and emotional backlash involved.