I was in the lead when our control slipped and the tunnel began to constrict.

And soon the tunnel began to lose its power over some of the others, as well.

The dark tunnel of demodand flesh began to close about him.

And before long the tunnel began to grow larger.

The tunnel itself began its formation in the Pleistocene period.

The tunnel began to turn more frequently as the very mountain narrowed toward its peak.

Soon, the tunnel began to curve gently to the right.

The second tunnel also began to drop slightly, but took longer to reveal its course.

The other day, the tunnel and two trains inside began filling with smoke.

He didn't have much time before the tunnel began to close behind him, shutting out most of the light.