The corridors were emptying of the last straggling students when Severus returned to the castle. By the time he reached the Great Hall they had all disappeared, which made the prospect of staying for a little dinner much more appealing than it might otherwise have been. He would normally have gone to his quarters and eaten alone, feast or no feast - once the children had gone he felt no obligation to make any sort of appearance - but tonight he found he wasn't quite ready to shut himself in alone. He was still too agitated to settle in with a book, and while he had no real desire to socialize this was better than plunging in with his thoughts again.
He went to his seat at the table, sat down without any greeting, and helped himself to some of the remaining food. He hadn't exactly dressed for the occasion, although it was possible that a heavy traveling cloak and questionably Muggle attire could pass for costume with some people.