It may not be immediately obvious from the text, but Mericet was the gargoyle. Teppic had been leaning on his camouflaged instructor all the time. This is another annotation which I am only putting in after repeated requests from readers. Personally, I feel that ‘getting’ this is simply a question of careful reading. But a quick straw poll of a.f.p. readers showed most were in favour of explicitly annotating it, so in it went.
Terry was once asked at a talk if he was always fully in control of his characters and events or if they tended to run away with him. The answer was: always in control — with one single exception. The whole of the assassin examination sequence in Pyramids was written “almost in a trance” with no idea of what was to happen next. It is one of his favourite bits.