As for why him, I was changing targets A LOT during this night, but these were my thoughts:
Lethal could very well be scum, but I figure the BG isn't Big Mans role so we can at least direct him while he's alive.
Sky could be scum but her being Masons with Big Man makes that slightly less likely than I'd like it to be. At least if I'd picked her and she flipped town we wouldn't lose much role-wise.
CP is being accused of being pretty much exactly the Traitor and while the points are compelling and his role is out there, I'm not in the business of actually committing to basically indy hunting yet.
So I went for OMB. I figured Ascetic might be a scum perk and even if he's left alive, he wouldn't do much except stick around until the game ends with pretty much no active part in the game. Also his scummy vote and subsequent statement that "town asked him to do it" seemed strange even for his standards and he never got back to me when I asked him what that meant.
Long story short, I went for a kill with meh scum equity but also just about literally no risk.
