De Hooch went over to the periscope and put his eyes to the binoculars. He could see two figures in heavy, dull-gray radiation-proof suits. They were lying flat on the floor, and neither was moving. De Hooch said as much. "The one on the left was moving his arm--just a little," Willows said. "I'll swear he was." Something in the man's voice made de Hooch turn his head away from the periscope's eyepieces. Willows' face was gray, and a thin film of greasy perspiration reflected the light from the overhead plates. The man was on the verge of panic. "Calm down, Puss," de Hooch said gently. "Where's Quillan and Laynard?" "They're in their rooms," Willows said in a tight voice. "Trapped. The bulkheads have closed 'em off in A. No air in the corridor. We'll have to dig 'em out. I called 'em both on the phone. They're all right, but they're trapped." "Did you call Base?" "Yes. They haven't got a ship. They sent three moon-cats, though. They ought to be here by morning." De Hooch looked up at the chronometer on the wall. Oh one twelve, Greenwich time. "Morning" meant any time between eight and noon; the position of the sun up on the surface had nothing to do with Lunar time. As a matter of fact, there was a full Earth shining at the moment, which meant that it wouldn't be dawn on the surface for a week yet. "If the cats from Base get here by noon, we'll be O.K., won't we?" de Hooch asked. "Look at the instruments," Willows said. De Hooch ran a practiced eye over the console and swallowed. "What were they running?" "Mercury 203," Willows said. "Half-life forty-six point five days. Beta and gamma emitter. Converts to Thallium 203, stable." "What did they want with a kilogram of the stuff?" "Special order. Shipment to Earth for some reason." "Have you checked the end-point? She's building up fast." "No. No. I haven't." He wet his lips with the tip of his tongue. "Check it," said de Hooch. "Do any of the controls work?" "I don't know. I didn't want to fiddle with them." "You start giving them a rundown. I'm going to get into a suit and go pull those two out of there--if they're still alive." He opened the locker and took his radiation-proof suit out. He checked it over carefully and began shucking his vac suit. * * * * * A few minutes delay in getting to the men in the reactor's anteroom didn't matter much. If they hadn't been killed outright, and were still alive, they would probably live a good deal longer. The shells of the radiation suits didn't look damaged, and the instruments indicated very little radiation in the room. Whatever it was that had exploded had done most of its damage at the other end of the reactor. Evidently, a fissure had been opened to the surface, forty feet above--a fissure big enough to let all the air out of A and B corridors, and activate the automatic bulkheads to seal off the airless section.