He looks back to her, eyes widening a little with surprise. And then narrowing with concern. This presents some considerations he hadn't really taken into account, but none that he can do much with.

"Oh. I...seem to have mistook this building's purpose, as well."

He crosses his arms awkwardly and steps away from the shelf. At least she isn't mad about it, apparently. He'd thought, perhaps stupidly, assumed that this was an archive.