...huh.
Usually this door opens to a little nook with a window overseeing the Quidditch pitch and a bookshelf that never has the same books, and he can watch Fredrick and Theodore practice and draw out rune-charts and dictate a long letter without being overheard.
Right now it apparently opens on a bar, with exploding stars out the windows and no one around.
He wonders if Minor and his friends documented this particularity when they took on that map-the-whole-castle project.
He sits down at the bar and pulls out the rune-charts.