I haven't iron nerves.

Not one second of that descent was less than hell.

I could hear the thunder of some kind of battering-ram on the door at the foot of the stair.
I could imagine the rope chafing against the sharp edge of the parapet as they paid it out hand over hand.

The only thing that made me keep my head at all was knowledge that Abdul Ali had had to do the trip feet-upward, with his head in a bag.

When they let go too fast it was rather like the half-way stage of taking chloroform.