A lot of paths in the TARDIS led to the closet.
All of this busy work was exactly why the Doctor hadn't noticed the Labyrinth popping up around the TARDIS. Oh, sure, the proximity alarm went off, but that went off every time a squirrel threw nuts in the TARDIS' general direction.
When the Doctor opened the door to head up to the school in order to teach his class, he found himself face to face with a wall of shrubbery.
He promptly closed the door and re-opened it to see if that had a different result. Nope. Leaves and twigs and other things used in topiary blocked his way.
"Personal space," the Doctor protested at the hedge. He pulled out his sonic screwdriver and scanned the Labyrinth. "Oh, no you don't." It was making that annoying noise that suggested magic or, as the Doctor preferred, 'Fandom's annoying forces that were unexplainable as of right now' to leave himself open to change the definition.
The door slammed shut and he returned to the centre console to fire up the engine. The TARDIS remained silent, not making the WHOOOOOSH WHOOOOSH sound he liked so much.
"Fine." He wasn't sulking, really, but he looked like he was. "Where did I put my plasma saw?"
[OOC: No Boom-De-Yada Science class today due to a stuck Doctor. Exam next week!]