He was lying on his back, stretched on a rough mattress at the farther end of the room, moaning slightly.

The two men exchanged quick glances.
"We are not going to have much trouble," Forrest muttered.

"What a beastly atmosphere! No wonder he's knocked up." Cecil, however, looked about suspiciously.
"Don't you notice," he whispered, "that we can hear the wind much plainer here than in the passage?
I believe I can feel a current of fresh air, too.

I wonder if he's been trying to cut his way through to the air-hole.

It's only a few feet up." He flashed his light upon the wall near where Engleton was lying.