But even then, you might think that this sort of thing is getting a bit ridiculous:
They heard him fumbling on the wall, and tapped again, to show him where they were. Suddenly, there came a click, and bright cold light and icy air rushed into their hiding place.Joan Aiken, The Wolves of Willoughby Chase
'I always wondered why that great knob was there on the wall,' James said. 'Well laws, miss! To think of your really finding the secret passage!'