It was more than likely.
The tears sprang unbidden to the young diver's eyes, but he dashed them away.
He must save himself, no matter what the cost.
He realized that he had been saved from death by drowning only because he was used to being under water a long time without taking a breath.
All divers practice this art, for possible use should anything become the matter with their diving outfits while at work.
He felt in his clothing and found his waterproof matchbox still safe.
Soon he had a tiny light, and seeing some dry driftwood at hand he set it on fire.
The blaze threw grotesque shadows on the rocky walls around him, but revealed nothing to his gaze but those same walls and the silent, underground stream flowing between them.
He was entombed alive!
Gradually this conviction forced itself upon him, causing him to shiver as if with the ague.