I see what you are saying. My thought process was, regardless of role, CFC seems like a danger. And if we get him, we'll know pretty quickly if Duck is also a bad guy. I mean, basically unless we find out he's a wildcard, we'll have a good idea that Duck must die.
But the situation is equally damning for Duck. We kill him, find out CFC was wrong and we know CFC is bad news. We find out CFC was right and then it's a question of stupid psychic or stupid bad guy I guess.