He looked harassedly around him. The Security man nodded and moved casually away. This was close timing. Something made Joe look up. He saw the catwalk gallery nearly overhead. The expected guard was there. Haney, though, was with him. There was nothing else in sight. Not yet. But Haney was on the job. Joe saw a Security man step out of sight in the scaffolding. He saw his own assigned security man speak to another, who wandered casually toward the Platform's base. Minutes passed. Only Joe could have noticed, because he was watching for it. There were eight or nine Security men posted within call. They had their walkie-talkies turned off and would be subject only to his orders if an emergency arose. Gongs began to ring all around the edge of the Shed. They set up a horrendous clanging. This was not an alarm, but simply the notice of change-of-shift time. There was a marked change in the noises overhead. A crane pulled back. Hammerings dwindled and stopped. There were the sounds of pipes, combined to form the scaffolds, being taken apart for removal. A sling-load of pipe touched the floor and stayed there. The crane's internal-combustion motor stopped. Its operator stepped down to the floor and headed for the exit. Hoists descended and men moved across the floor. Other men scrambled down ladders. The floor became dotted with figures moving toward the doors through which men went out to get on the busses for Bootstrap. Nothing happened. More long minutes passed. The shift brought out by the busses was going through the check-over process in the incoming screen room. Joe knew that Major Holt had, within the past five minutes, gathered together a tight-knit bunch of armed security men to be available for anything that might turn up. The men doing the normal shift-change screening were shorthanded in consequence. The floor next to the exits became crowded, but the central area of the floor was cleared. One truck was stalled at the swing-up truck doors. Its driver ground the starter insistently. Suddenly there was a high-pitched yell away up on the Platform. Then there was a shot. Its echoes rang horribly in the resonant interior of the Shed. Joe's own special security man hurried to him, his face tense. "What about that?" "Hold everything," said Joe grimly. "That's taken care of." It was. That was Mike's gang--miniature humans popping out of hiding to offer battle with missiles carefully prepared beforehand against their alleged associates in sabotage. One of the associates had drawn a gun and fired. But Mike's gang had help. Out of small air locks devised to make the Platform's skin accessible to its crew on every side--provided they wore space suits--dark-skinned men appeared. The security man's walkie-talkie under his shoulder made a buzzing sound. He reached for it. "Forget it!" snapped Joe. "That's not for you! You've got your orders! Stay here!"