That earns a quirked eyebrow. "Mm. Apparently there's one on the third floor, though nobody seems to know exactly where. Another on the fourth... somewhere."

He shrugs. Something for another day. "Bit of a shame if we did find them. Then I suppose you'd have to tell somebody."

Sherlock doesn't intend to use them, maybe, or not often, but it'd still be a shame. One secret fewer for the castle to hide.

"Anyway. Not important. Isn't as though anyone is using them if they can't find them." He stops in front of their door, the 'cursed' classroom which he's quite convinced is nothing of the sort, and nods his head at the door.

"That's us, then." He hesitates, wicked thing that he is, a thoroughly amusing and decidedly unkind idea forming itself in his head, and then: "Be careful."