Of course she'd had a reason to leave. People didn't get up out of bed and wander around for a stroll at midnight simply because they were bored. Well, he should amend that; he'd believed one student who told him that, though she'd still gotten detention for it. Most people, however, had a reason.
Excuses and reasons were two entirely different things, however, and he noted which one she'd used. He had said excuse himself, but it was still a point worth noticing. He was about to continue when she tuned, seemingly forgetting he was there. "What's missing, Miss Eckstein?" he asked levelly. Given the area of the castle they were in, what should be...
Oh. Merlin, this wasn't good. Severus kept his expression controlled, but was inwardly cursing. He'd nearly forgotten about the Room of Requirement, but he didn't particularly want his students finding it again.