Branwen heard the other girl's mounting frustration with the door. Her frustration was mounting with her book, where she couldn't find what she had sworn she had read. She flipped through the index to no avail. Then she used a little charm she had read once which skimmed the book for cases of the word you were looking for. Unfortunately, 'door', 'room', and 'locking' came up too many times to be of much use.
She slammed her book shut, and turned to Vicky. "That was a dead loss. We could always try unscrewing the hinges or blasting the door off? That's what they always do in the movies." And while admittedly the movies weren't real, magic had to tip the balance in their favour, didn't it?