Klaus is not sure what is going on, and goes as far as to turn around to check that there isn't anyone behind him, since he can't rely on his senses the way he used to. The compulsion didn't work, that much is for certain, but what is going on here? There is no one behind him, and he isn't sure what Gaius is looking at for so long, or who he says yes to before looking back at Klaus.

"Silly," Klaus echoes, with faintly amused confusion, because he would have used the word crazy right about now. Or maybe not, who knew. If vampires, werewolves and ghosts existed, who knew what else might in other universes, that Klaus might not be able to perceive? "Is there someone else here with us, doctor?"