Zack implicitly claimed to have blocked Csargo's kill, and Monty just didn't get that that's what Zack was doing and kept questioning what Zack was doing. My feeling, and I think this was what Zack felt also, was that scum wouldn't act that way in that situation. They would understand what Zack's vote was about and they would be trying to distance themselves from Csargo. They would not be making Zack spoonfeed them his claim. In fact, read GH's reaction to see a likely scum reaction.
Bookmarks