He stepped to a corner of the room and by a ring he raised a trapdoor.
At this juncture, Pierre and Paul Lanier emerge from a trapdoor, cutting off escape.
There was a trapdoor in the floor that was right over the river.
The trapdoor had been left open, and I thought that was the place it came through.
Again he followed, mounting by a ladder, through a trapdoor on to the ...