The door had not been locked, since Hermione had come through it only hours before. Employees rarely went to the basement at all, much less out to the unappealing backyard. She pushed it open slowly, since moving too fast caused the hinges to squeal loudly. The door closed on its own, blocking out the wind as it did. She and Echo both shuddered in relief. Hermione lowered the scarf from her mouth and nose and took several deep breaths before moving to a stack of boxes on the far side of the room. They were easy enough to shove aside, revealing a cleverly-hidden trapdoor. It took a moment of feeling around the dark wood before finding the ring used to lift it.