Why indeed? Like I said, I have no idea! I was hoping maybe someone reading this could make me find out!;p (Just kidding - but you're pretty great with prompted drabbles, so if anything should occur to you...)

Well if you ignore the possiblity of Don Flamingo controling Usopp. Zoro would probably be possesed and needing to be stopped from hurting everyone else. Or could be someone pretending to be Zoro and Usopp is seeing if it is really him. Or could be them working together to trick some other enemy.