Hmm, this is surprising. At first I thought you're providing examples of bonding behaviors that don't raise oxytocin levels, but decided to google anyway, and voila: Oxytocin and the Biopsychology of Performance in Team Sports, Gert-Jan Pepping and Erik J. Timmermans.
The second example, killing others with allies in combat, seems to be similar to team sports. However, the third one, being held in captivity / abused, seems to be different in kind. Do you have any sources on it?
Edit: I wonder if playing a team-based competitive game like Team Fortress 2 has any effect on oxytocin levels, in addition to dopamine effects that are typical for video games?
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.