If the woman hadn't already come through here, he would have given up at 
this point, thinking it a dead end, a busted tunnel that had failed to expand. 
The drumming was now coming into his ears and bones from all sides. He could 
not see a thing, though from time to time he thought he caught a glimmer of 
flickering yellow light. The tunnel undulated slightly in the deep currents, 
rivers of bitterly cold water swirling along the floor of the straits. Whenever 
he allowed his mind to wander, reminding himself that he was deep below the 
surface of the ocean here, he had to stop and force himself not to panic. 
Concentrate on the nice air-filled tunnel, not what surrounds it.