And when the sentry had passed the rope, Boris slipped over the parapet and started his descent.

He had to come quickly for he had less than two minutes to reach the ground and join Fred in his shelter.

Down he came, hand over hand, so fast at the end, when he just slid, letting the rope slip through his fingers, that he must have burned the skin from his palms.

But he made it, and came running toward Fred.

He was crouched low against the ground.