Regulus stopped and turned around to look at Severus. There was a little frown on his face. "Okay, that's new. None of us went through... whatever it is you just did."
He took a step closer and cautiously put a hand on Severus' arm. "Are you all right?" he asked with a little worry, because this man might be the famous Severus Snape for most people, but it was just Severus for him, even if in his eyes, he was a much younger man.
"What year are you from? You were already headmaster, weren't you?" It was the one thing that made sense. "We haven't been able to get through the gargoyles to reach the headmaster's office, but you feel the castle." Being headmaster would explain that. "Great-great-grandfather Phineas always said that he could feel the school come alive with people on the first of September."
He stood where he was, giving Severus the time he needed. "We can sit in the Great Hall until you're better. You might want to know all the different players and who knows what about a certain Dark Lord. We're stuck here, but we don't know who else is coming through."