Nate saw William — Mister Beckett? Fuck, he was still getting used to the fact that his schoolmates were now his teachers. And librarians — about a split second before he crashed into him, far too late to even attempt skidding to a halt. Whoops. Maybe he shouldn't have taken that corner so quickly.
"William!" he said, taking in a few deep breaths. "Uh, I mean Mister Beckett. Sorry." He untangled himself from William and shook himself out. "I was trying to get back to Hufflepuff, actually. Or somewhere with actual people."
He hadn't actually meant to be out on his own. He'd been in a huge group of 7th years, most of whom had decided that they were old enough and experienced enough to take on a few house elves without faculty supervision. The problem was that half of them had heard a weird noise and split off, and then even more had gone to check out what they thought were sparks, and then Shaila and Hortense had had to go to the bathroom. Nate had made a minor detour to peer into one of the less-used hallways, and when he'd come back, he was all alone.
Obviously, in five years of war, nobody had learned how to do an accurate head count.