Free Payback by Keith Douglass

checked the oil rig. He was so close now he couldn’t see the top two levels. He could spot nobody on the first story. One more long look around, then he swam down and worked toward the depths. He leveled off at what he guessed was eighty feet and did a slow circle, watching every way around the compass. He spotted no swimmers, but his visibility was no more than five feet down this deep. He could still see the lights of the tower above, although now they were faint and wavering.
    Time to start up. The sonar should have picked him up by now. Where did they have the sonar setup? How powerful was it? He leveled off at fifty feet. No swimmers, no spearguns, no bang sticks. He wondered if a bang stick would disable a man as well as a shark? He knew it would. The CO-2 set off by a shotgun shell would slam through a wet suit and gush inside the body cavity, expanding rapidly. It probably would collapse both lungs and balloon the body,sending it floating quickly to the surface. He should have a few for the SEALs.
    At thirty feet he paused again, then swam around the square legs of the tower. No enemy divers. Why? If they had regular scuba gear they could easily go to thirty feet. The old Draegrs were set to work at a maximum of thirty-five feet. He looked upward watching for any shadows crossing the pattern of light from the hundreds of bare bulbs burning on the platform. Nothing. The third time he swept the area he found a swimmer. High up, maybe at fifteen feet.
    Could the ones running the sonar communicate with a swimmer in the water? He didn’t know. If they had sonar, they might have a way to use voice through the water to a swimmer. He’d have to check that out. Upstairs. They were watching for him up there. They? He watched for another fifteen minutes and saw three swimmers. They came together for a conference evidently, then parted. Two went out of sight and the third one stayed on Murdock’s side of the platform.
    He knew now the swimmers were there. Time for more surveillance. He swam down to the bottom. He wasn’t sure of the depth as he began to swim around the tower in ever-widening circles. Out about fifty yards on the west side of the tower, he found a strange structure on the sea floor. It was a dark blob, but definitely man-made. He didn’t want to use the one waterproof light he had. Up close he estimated the concrete-looking dome of a building was fifty feet square and fifteen feet high. There were no pipes, tubes, or wires extending from the structure on any side he could see, and no entryway on the sides or top. He pulled away from it and swam toward the tower and upward.
    At fifty feet he paused again and watched for the shadow divers above him. Once more they gathered, probably exchanging notes on write boards, flashing small lights. Then they parted. Murdock drew his KA-BAR and powered upward at the lone diver on his side of the tower. The guard swimmer moved slowly back and forth as if walking a post. Murdock came up beneath him and touched his foot. The man reacted at once, drawing a knife and turning to face Murdock. The Navy SEAL powered straight at the surpriseddiver, batted away his knife hand, feinted one way, then drove in the other way, his KA-BAR slashing and tearing at the diver’s face mask and air tube. The man wore air tanks and was clumsy in his turns. Murdock dodged one way, surged upward as the airless diver clawed his way toward the surface. Murdock caught him and drove his blade deeply into the man’s stomach, then jerked it out.
    He saw a second diver coming from his left, and pivoted around in the water. Murdock pulled the speargun from his leg, and when the diver was ten feet away and waving his fighting knife, Murdock fired the first ten-inch steel shaft. It hit the attacking diver just under his clavicle, missing his heart and lung. The diver soared upward out of the fight. Murdock waited, but no third diver appeared. He had no prisoner. He swam down to