The hands and arms and fingers of the waldoes in the screen worked together with precision as they put the last finishing touches to the generator unit. Finally they were finished; the arms assumed the "ready" position. Crayley almost held his breath. Everything depended on Klythe now. Klythe, with his impatience, his pride in a piece of work well done, his eagerness to be sure of perfection; Klythe himself was the only weak link in the chain that led to his own death. The tunnel was still flooded with radioactivity. In production, that wouldn't matter; the next set would slide into place and the hands would begin again. But this was a test run; the record would be allowed to run to the end instead of recycling, while the huge pumps replaced the argon atmosphere with air suitable for breathing. The radioactive stuff was pumped to a cooling chamber, where its silent violence would be allowed to expend itself below the danger point. Five minutes. Crayley could see in his mind's eye that tape running through the pickup head, running through five minutes of nothing. Then a light flashed above the door to the tunnel as the detectors signalled the all-clear. It was safe to enter the tunnel now. Crayley found himself clenching his teeth for a fraction of a second before Klythe opened the door and stepped through. There was a long, almost timeless instant as Crayley watched Klythe's face on the screen. Then there was a sudden sound, a brilliant light, and the screen went dead. * * * * * Crayley smiled inside himself as he yelled and sprinted out to the tube lift. The hidden hand of the secondary had reached up and ripped off the regulator coil--housing, innards, and all. The resulting explosion had been felt, even up here, as a dull rumble. The lower level was a mess. The emergency door had slammed down to prevent the spread of contaminated air, and the huge pumps were going full blast to clear the area. At the first door, Lesker, one of the safety engineers, stopped him. "You can't go in there, Lew. One whiff of that stuff, and you'd be gone." "What happened?" Crayley asked briskly. Lesker shrugged. "Who knows? That new generator blew, somehow. Not much harm done, really; as far as we can tell, the only real damage was in the tunnel itself. The temperature must have averaged better than a thousand Centigrade for a few seconds, though it was a lot hotter than that at the center of the blaze. It's cooled down a little now, but that generator must still be burning." He stopped for a second, then: "Nobody got out of it alive. We're sending in the mobiles now. The secondaries in there won't work. It's going to be a rough job because we'll have to use cables; we couldn't possibly get a UHF beam through that static." The safety men were setting up a monitor screen bank for the mobile waldoes. Two of them, four-foot wheeled robots with TV cameras mounted where human heads would be, rolled up to the closed door.