The technician busy filling the fuel tanks of the rocket was the third man to go. He managed to finish closing the filler cap and to lay down his flexible line before the urge to sleep overcame him. By this time the guards knew that something was wrong. Silence came over the cavern. In the stillness, the note of the violin flickering up and down the scale could be heard. Men looked at each other in growing apprehension. Looking, some of them lay down and went to sleep. "Sleep gas!" an officer bawled. "Shoot all foreigners on sight!" The officer suspected that some spy had slipped into the underground cavern and had released gas there. His command was intended to enable his men to find and eliminate this alien. As such, from a military standpoint, it was a good command. It had this deficiency: when his men did not find any aliens, but their own people continued going to sleep on them, they began imagining foreigners. The guards began to shoot their own technicians and engineers. As panic swept through the cavern, guards began to shoot other guards. Soon the people in this huge underground chamber were tearing and destroying each other. And one other thing: they were also going to sleep. The panic grew to hurricane proportions. When Kurt Zen appeared inside the cavern the whole vast place was as still as a tomb. Smoke from the rifles hung in the air, the cavern stank of death and fear. But the bomb still rested in its launching cradle. Zen took one long look at that bomb. He felt his sigh of relief clear down to the ends of his toes. At the sight, the last remnant of pain vanished from his toes and fingers. Not that the damage done by the matches did not still exist. It did. But in the surge of elation that swept through him, he completely forgot the pain. "We just got here in time," a man said, appearing beside him. It was Spike Larson who had spoken. Awe on his face, Larson glanced around the cavern. "They started killing each other. They must have gone nuts." "I don't blame them," Zen said. "I damned near did, on the way here." "That trip through nothing is sure a stinker, isn't it," Larson answered, grinning and shaking his head. Zen agreed with him whole-heartedly. After tuning his body to an instrument in the cavern, hidden so well that Cuso's men had not had time to find it, West had punched a button. The machine had vanished. West had vanished. A horrible moment had come when it had seemed that his feet were standing on nothing more substantial than air. What he had felt under his feet had, in fact, been far less substantial than air, which had body. It had been even less solid than space. It had been _nothing_. Swishing, colonel Grant came into existence on the other side of Zen. Grant looked fussed, but he gripped the rifle he had taken from one of Cuso's men with determination. "Just between you and me, I'd rather fly a space satellite to Mars any day in preference to facing this jump."