And then the oxygen was gone. He had just time to gulp in one last lungful as the hissing died and the bubbles around his face stopped. Once more he heaved at the wires, using every ounce of power his body could muster.
Then, holding his breath, he rolled sideways into the gap he had created. The slackened wires sagged down and the cruel barbs bit into his chest and back and legs.
He winced at the pain as he tore his hands loose from the deeply embedded prongs, then pulled the wires away from his chest and rolled his body further into the opening. The points dug into his chest again while he moved one leg and then the other.
When he knew he could hold his breath only a few seconds more he broke clear with a lurch that left bleeding furrows across his body and floated dizzily toward the surface. One hand whipped the useless, empty oxygen bottle from his face.
He sucked in the thin air of Mars with harsh, rasping, grateful breaths as he broke surface, glancing around to restore his sense of direction. He was inside the barrier.
Seven of the armored cars were lined up along the southern boundary of the camp, the focusing coils on the muzzles of their proton cannon glowing red from continual firing, their powerful lights picking out targets for the gunners. As Nick swam on, one of the cars tried to move forward and struck a soft spot in the muddy ground. Its light waved wildly, then went out as the car overturned and rolled into the water.
High above the dark water the hull of the spaceship glowed in the starlight. Nick headed straight toward it, sometimes swimming, sometimes floundering through deep, sticky mud that sucked tenaciously at his feet. Even in the darkness and confusion he knew his way, for Central Camp had been his home for many months.
As suddenly as it had appeared the water began to recede, draining into the ground. Nick understood. The barrier had been breached, and Martians were not able to swim. The heavy combat vehicles of the Exploiters were bogged down in the mud, but from the sounds of firing Nick knew that a good many Mecs had gained the safety of the high, unflooded guard towers. With daylight the surviving Martians would be forced to retreat.
There were still many deep pools of water about, and a layer of slippery silt over everything, when his route took him close to the administration building. He edged quietly around the corner just as a wet, bedraggled figure floundered through the mire to the doorway. The figure, outlined for an instant, was human enough, but to Nick it seemed somehow wrong. Quickly his mind placed the discrepancy. The man wore a coat instead of the short uniform jacket of the Mec.
Mud sucked noisily at Nick's boots as he followed, but the sound was drowned in a renewed burst of gunfire. Nick smiled grimly as his killer training awoke again under the influence of familiar surroundings.