Just beyond the mesh lay a chunky man in a gray, company guard uniform. He had a gun in his hand. He was intact except that the top of his head had rolled about a foot away. It had been sliced off tidily just above the nose by something hot. Phil remembered how neatly the blue needle had sliced the steel beam. He hurried past toward an open arch just ahead, and jerked back from a large gray snake coiled there. Then he saw that the snake was a robot doorman like Old Rubberarm, and looking higher he saw that it had been sliced off close to the wall. Mitzie and the rest came through the mesh. Carstairs kneeled eagerly by the dead man and examined the gun he was clasping, but a moment later got up with a shrug. "Not an ortho, eh?" Buck inquired. "Usin' those sing'lar missiles, you'd think they'd be up to date in other things." "No, just an ordinary gas gun," Carstairs told him. "But we can be pretty sure his head wasn't taken off by a red hot buzz saw. The others must have orthos." He turned on Phil and grabbed him by the lapels of his jacket. "Look here, clown," he said quietly, "who are those others? You must have known someone was going to break in here tonight. You were counting on that door being open." "We are a bit like jackals, aren't we?" Phil remarked dreamily. Carstairs twisted his jacket. "Who were they?" Phil didn't react, but he did jerk around suddenly when he heard Moe Brimstine say metallically, "Whatcha want, Mack?" Llewellyn had pulled out the stub of gray robot arm sticking from the wall. "Quit that," Carstairs ordered curtly, letting go of Phil. "Take it easy, Carstie old boy," Llewellyn said with a smiling flash of white teeth. "Here's a bit of an odd thing. See where whatever sliced this robot arm cut into the wall beyond? Well, follow back from the cut in a straight line through the slice in the robot arm." Like the others, Phil followed Llewellyn's directions and saw that the straight line ended in a deep cut in the floor a half dozen feet behind them. "I don't git it," Buck said. "You mean somebody shot some kind of beam from the next floor under us?" Llewellyn said, "Hardly. The evidence points to a gun that shoots in opposite directions at the same time. I fancy that if we'd have looked behind us at the head of the stairs, we'd have seen some cuts mirror-imaging those in the mesh." He thinned his eyes at Carstairs. "I'm beginning to think orthos are rather strange weapons, Carstie old boy." He glanced at Phil. "You said they're blue and sizzle, Mr. Gish. Do they also backfire?" "Say, look at this here communicator," Buck interrupted. He had been poking around the side of the corridor behind the guard. "One button's got a new-looking gadget rigged up to it that's pushed it twice now while I've been watching."