If I did not cry out it was because fear
had me by the throat; and if I did not fall, it was more by heaven’s mercy than my own strength. It was not the only that the flash  shone in on every side through breaches in the wall, so that I seemed to be clambering aloft upon an open scaffold, but the same passing brightness showed me the steps were of unequal length, and that the one my feet rested on at that moment within two inches of the well.
This was the grand stair! I thought; and with the thought a gust of a kind of angry courage came into my heart. My uncle had sent me here, certainly to run great risks, perhaps to die. I swore I would settle that ‘perhaps’, if I should break my neck for it; got me down upon my hands and knees; and as slowly as a snail, feeling before me every inch, and testing the solidity of every stone, I continued to ascend the stair. The darkness, by contrast to the flash, appeared to have redoubled; nor was that all, for my ears were now troubled and my mind confounded by a great stir of bats in the top part of the tower, and foul beasts, flying downwards, sometimes beat about my face and body
The tower, I should have said, was square: and in every corner the step was made of a great stone of different shape, to join the flights. Well, I had come close to one of these turns, when, feeling forward as usual, my hand slipped upon the edge and found nothing beyond it. The stair had been carried no higher: to set a stranger mounting it in the darkness was to send him straight to his death...

    To this day, I am afraid of climbing stairs in the dark and, like David Balfour, crawl on all fours, confident that someone has chopped the steps away before me in the hours since I last went up there. This irrational fear is usually accompanied with imaginary thunder and lightning, leaving no doubt about who is to blame. Oddly, I’ve never been afraid of being Kidnapped, which my mind was convinced could only be a doorway to another great adventure.