They found the guards already waiting to take them to where Miles was, and followed them down to the entrance of the explosion testing chamber. Miles was smiling and chatting with a man who appeared to be a perfectly normal rocket pilot, and who seemed bored until he saw Norden. He consulted a picture on some kind of tape recording and stepped forward. "I have orders to deliver the K-40 to you, Dr. Norden," the pilot said. "But it's pretty bulky in its containers. If you'll come out to the ship and okay it...." Miles cut in blandly. "I've been explaining the new regulations, Dr. Norden." He winked slightly, with a faint motion toward the chamber. "Go ahead and clear through," Norden told the pilot. "I'll wait, and then we can look at your cargo. It's a damned nuisance having to hold things up while everyone is X-rayed. But we've new regulations now." He caught Miles' look of approval, and he knew he'd reacted correctly. The pilot shrugged. "Why not? Let me know if you find any dangerous diseases." He chuckled, and stepped through the entrance, and out toward the fluoroscope set-up. The picture on the screen was satisfactory and the guards started to relax beside the slits where their guns projected into the chamber. Miles glanced at them, and his voice was urgent, commanding. "_Shoot to miss. And keep getting closer._" Another screen showed the pilot turning to leave, just as the first bullet splintered the floor a yard from his boots. He jumped back with a terrified gesture. Another bullet came closer, and a third barely missed him. Shock hit his face, and vanished as he turned into a bright splash of greenish-yellow light. "They over-estimated our production and under-estimated our ability to bluff," Miles said. "Good shooting, men. I'm glad he decided he'd failed the test before you had to shave it closer." Norden stood staring at the blasted area and back toward the screen that had shown the image of a normal human standing before a fluoroscope. Breathing vacuum for five minutes hadn't hit him as hard. Subconsciously, he'd counted on the fluoroscopic evidence--and it had proved to be a lie. "He couldn't have been an Alien with that kind of a skeleton!" he whispered. Miles shook his head. "He wasn't. As near as our cyberneticists could gather, he was some kind of a robot, designed to mix with us. We left automatic televisors on Mars to catch a few telephotos of the Aliens, and they look a little like octopi on stubby legs. Nothing could make them look human." "But a robot with a human skeleton?" Pat asked. "It's possible, with enough advanced development. Hide the metal works in the so-called bones and skull, and shape everything else to the right form and transparency. Probably the first ones we caught were meant to mislead us. Hughes swears that any race capable of developing such an advanced cybernetic brain could handle the rest--down to letting him get his energy out of our food."