I can see how from the Final Four’s point of view, it could be self-defense, but not from the larger Colonial society’s or a legal point of view. I believe self-defense defenses only apply to defending oneself from immediate harm, and if you’ve got somebody locked alone in an airlock, you’ve already removed the threat of immediate harm.
I wonder, though it would be a cruel solution, if the Four might not turn it right back around and accuse Cally of being a Cylon, and let Colonial justice/paranoia take care of her for them. It would be more risky in the short-term, because Cally would make the counter-claim that they’re Cylons, but nobody can prove that anybody is one of the Final Five at this point. They can probably guess that, since Athena hasn’t figured out that Anders and Chief are Cylons, she can’t specifically tell who’s a Cylon and who isn’t. They also know that Kara’s identity is in question, so the government hasn’t figured out a way to tell who’s who yet, either. I doubt the Final Four will take that approach, but it would be interesting if the Final Four started a witch-hunt.
