"`And there's the sign, Ridcully,' said the Dean. `You have read it, I assume. You know ? The sign which says "Do not, under any circumstances, open this door" ?´ `Of course I've read it,' said Ridcully.`Why d'yer think I want it opened ?' `Er ... why ?' said the Lecturer in Recent Runes. `To see why they wanted it shut, of course.'