It had been a snap decision, and the only one that would save their lives. With the expanding cloud of carbon dioxide gas completely surrounding them, they had to turn to the water. Summer considered cutting the anchor and making a frantic run through the vapor, but if there was any delay in starting the engine and fleeing they would die. Plus, there was Dirk’s life to consider. If he happened to surface under the stern as they got under way, he could be cut to ribbons. He might have little chance of surviving as it was, but there was always hope he could outswim the gas with his remaining air.

“We’ve got to get into the water,” she yelled as the gas erupted. Trevor saw her step toward a fully rigged dive tank on the side rail.

“Get into your dry suit. I’ll grab the tank,” he directed.

With less than a minute before the boat was engulfed by vapor, Summer jumped into her dry suit and grabbed a mask while Trevor hastily buckled on the tank. She barely had time to slip her arms through his buoyancy vest straps when the carbon dioxide wafted over the boat. They fell more than jumped over the side, splashing loudly into the cold water and submerging beneath the lethal cloud.

Unprotected from the cold, Trevor felt the immersion like an electric shock. But his adrenaline was pumping so hard that he didn’t freeze up. Clinging together face-to-face, they kicked awkwardly through the water, passing the regulator back and forth for shared air. They eventually worked into something of a rhythm and soon made good headway toward the island.

But the cold quickly caught up with Trevor. The effects were imperceptible at first, but then Summer noticed his kicking slow. His lips and ears showed a tinge of blue, and she knew he was drifting toward hypothermia. She increased her kicking pace, not wanting to lose their momentum. She struggled another hundred feet, realizing that he was slowly becoming a deadweight. She looked down, hoping to find the seafloor rising up beneath them, but all she could see was a few feet of murky water. She had no clue as to how far they were from the island or whether they had in fact been swimming around in circles. The time had come to risk surfacing.