Currents of water still swirled around them and tugged at the two men. But it had much less force than during the downward descent. Alec unclamped the seat belt, then slammed his magnetic clamp suit boots against the outer plates of the carrier. His suit buoyancy dragged him into an awkward crouching position and he swayed and fought against both the upwards lift and the current swirl. "Let's go," he said. * * * * * A hundred and seventeen feet above them, Hall and the crane operators could hear the hollow clang of the magneboots as the two engineers inched their way back alongside the tractor to a spot where the tractor hull touched the pump housing. Alec cut one foot loose from the vertical side of the tractor and slammed it against the pump base and then quickly shifted the other foot and began forcing his way down under the curve of the tube. Troy followed. In the shelter of the base and tube, the current no longer pulled at them and it was only the suit buoyancy to battle. It took them three minutes to struggle their way to the juncture point. Alec wedged himself in with his back against the housing above him and carefully began unwinding the explosive belt he was wearing. With his feet clamped on the vertical wall of the pump housing and knees locked in a skier's stance, Troy handed over the first of the magnetic clamps. Alec took it and carefully clamped the end of the plastic explosive belt against the pile housing. They worked slowly but steadily until the entire band of explosive was in place along a five-foot arc of the housing. During the entire operation, neither man spoke and on shore, the listeners could hear only the heavy breathing of the pair and an occasional muffled sound of a clamp going into place. When the plastic was locked down, Troy carefully unclipped a timer fused from his belt and handed it across. He spoke for the first time since they left the tractor. "It's set for seven minutes." In the wavering light of the murky waters, he saw Alec glance up at him and then gingerly insert the fuse into the explosive. "Get moving," Alec ordered. Troy started inching his way back along the pump housing wall. Alec waited until Troy moved into the gloom and almost out of sight, then flipped the water-tight switch that activated the fuse. The device was armed. In seven minutes, if the pile didn't go critical before then, the charge would detonate--whether they were back on the surface or not. He shoved himself free of the pile housing and followed Troy back along the wall of the base. At the hull of the tractor, he made the foot-at-a-time crossover and again fought suit and current to get back to the cab. The seconds ticked off into the first minute and into the second. Ahead, Troy had reached the aperture of the cab door and reached in to grasp the end of the steel safety belt. He hauled himself into the seat and looked back for Alec.