Phalanx watches the exchange and appropriately grins at Vincent's rude gesture as if the whole thing makes perfect sense to them--in proper context and everything. Their eyes are still the empty, soulless eyes of a doll, but they're otherwise easy to mistake for a normal, entirely-lucid human for a moment.

However, the fuzzy points of pain, and blood that seems much too old and sluggish to be in a living body, is still a dead giveaway if you can sense that kind of thing.