Aaaah, damn good point about Cain and the not-liking-to-owe-anyone. I expect there's some truth to that, but I hadn't looked at it from that angle.
Hah, "good cop/bad cop" was exactly the way I described that bit. Totally prearranged. :P
The Mystic Man made Cain promise to stay with DG, but I do wonder if he wasn't glad for the excuse, or at least the relief from having to choose between keeping the group safe or going after Zero.
You know, you just made me look at that from a slightly different angle. Cain seems to do a lot of what he does out of a sense of duty. It could be argued that he felt he was duty-bound to avenge his wife. His own words are "I'm gonna have to kill him." Have to. Then he becomes conflicted when another duty -- protecting/aiding DG and company -- interferes. Yes, it's very likely that he WAS relieved when his promise to the Mystic Man trumped his other obligation.