That doesn't surprise me so much. I mean, he's probably right whatever he thinks about those things sapping energy, technically. Though I don't think they take you to a pocket dimension or anything either.

[He'd also known in advance that wendigo exhibit decay on top of their cervine traits - but of course, Mahiru somewhat appreciates Fuyuhiko's more prosaic approach.] So... it sounded like you'd already told him all the stuff that happened "later", like Komaeda plotting against Akane-chan. [This is the logical conclusion about the identity of the traitor to which she has jumped in the time she has had to mull over the matter.]