A point for your consideration, whilst I catch up:
Assume I'm Cabal. Somehow, I use my winning smile and boyish charms to ensorcel members of the Tower: I convince Vector to jump to my defense on Day 1 and look like she's buddying me. After that, Jim and I butt heads for ~50 posts, and in the end I somehow manage to convince the Tower of my virtue, and earn enough Assists to beat Org.
Then, after winning the match and just as I cause Jim to doubt his accusations of me, I decide to burn that potential bridge and Cabal-kill him. Why not?
Day 2 starts, and a case starts to build on Vector, primarily for her behavior in assisting me the day before. I decide to risk the small measure of security I'd earned and return the favor she inadvertently performed for me midway through Duel 1, in being the first to turn the Assist Votes around. I relate to everyone how her helping me doesn't make much sense for a Scum ploy, and therefore that she's likely to be Tower. This seems to satisfy the leaders of the case against her, and though it makes me look bad I might have earned a buddy.
Then, after taking that minor risk and investing energy into gaining a new buddy, I decide to Cabal-kill her too, again for the hell of it. Why not?
If it isn't plain enough, allow me to clarify. If I wanted Vector dead, I'd have jumped on the case against her and pushed her into the ring D2, rather than trying to turn the vote around, and in the process making myself look bad. Being the target of her actions, I'd have had a reasonable chunk of argumentative clout to bring to bear. That way, I would have saved my Nightkill for someone else.