At that tentative touch, Severus unfurled out of his own huddle, turned to face Al, reaching out for him instinctively, gathering him close, wrapping long arms around him and just holding on.
"We won't be unprepared. It's slow. We'll have days, perhaps many days. I'll be able to estimate more precisely soon. We'll all know in advance, when they can break in. There'll be a fight.
Al, listen to me." It was low, intense, breathed into the tousled hair. "When the fighting starts, I don't want you anywhere near it. I want you to stay as far away from it as you can. No matter what you see or hear. No matter what happens. Promise me."