Well, almost everyone has him equipped with the Brotherhood at that point, right? It's a water sword, it's made of water, and blended in with the sphere pool so no one noticed it.

MY question is, if they're carrying around the weapons, and the monster attacks have made everything too hectic to keep track of, why did no one take the opportunity to slit the throat of a couple of the Luca Goers? I mean, they're there in the pool with you, and no one is watching anymore. Get some revenge on those annoying twits.