Way, way, way more than he bargained for. Now, he isn't exactly going to be increasingly horrified by the explanation, but that doesn't mean he won't look at least perturbed by it. It doesn't help that just before getting stuck in the carnival, he was stuck preparing for a few trials of his own (exams, technically, but knowing Mephisto...).

"...sheesh, that sounds more like they were trying to kill you all off than anything else," he says after a moment of just outright staring. "The worst test I ever had to deal with was when they locked us all in a building with a bunch of ghouls and that definitely did not end with drinking poison."