Morag followed the voice and walked around the corner where she found Marietta, standing in front of a door. "Strange. I never knew there was a classroom here." Morag said, thoughtfully. After a minute she shurgged. "Oh well, there's probably lots of classrooms I don't know about. Hogwarts is a huge place. So was it the library or the comon room you were looking for?" she continued, not overly worried by this door.