Behind him, chaos and rising voices. A com-box blared, "All guards alert! Escape! This prisoner's dangerous! Don't let him get off the ramp! All guards alert!..." Forspark lights flared at the gates. Somewhere a surface carrier rumbled into clattering motion. * * * * * Boone sagged back against the warehouse and swabbed the blood from his eyes. Then, still breathing hard, running almost doubled, he raced not towards the gates, but away from them, towards the black block that was the airlock power station. Shadows again, and another pause for breath. Sirens blasting. The rumble of more carriers. In spite of his tension, Boone smiled thinly. Swinging round, he moved warily on towards the station entrance. The two men on duty stood in the doorway, peering out across the ramp. Back flat to the wall, Boone silently edged towards them ... closer ... closer.... One said, "What's that--?" and started to turn. Boone leaped forward, triggering a beam from the nerve-gun. The two duty men went down as one. Dragging them inside, Boone kicked the door shut, then turned to the lock control equipment. In seconds, he had levered out the gear that prevented the outer locks from opening till the inner were closed and sealed. Crossing to the emergency control bank, then, he threw the first switch. Heavy-duty motors spun to droning life. A red light flashed on the board. Ten seconds later the red light clicked off. A green light blazed in its stead, and the motors cut off. The inner locks were open! Dry-lipped, Boone threw the second switch. Motors. Red light. Green light. Silence. Or almost silence. For now a whistling sound came dimly, apparent even within the building. The sound of the ramp-bubble's precious atmosphere escaping! Swinging up a heavy beryllium wrench, Boone smashed the switches. That made his gamble good for fifteen minutes' leeway ... a quarter of an hour at least that the locks would stay jammed open. Boone threw down the wrench. Then, pivoting, he strode to the door and jerked it open. On all sides, in the distance, men were running, shouting. There was a low roar of atmosphere compressors, trying to compensate for the changing pressure. Now sirens blasted. While he watched, a surface carrier skidded around a warehouse and hurtled towards the airlock power station. Ice-nerved, Boone waited, weapon ready. The carrier screamed to a stop beside the door. Men leaped down. Boone stepped from the shadows, swung his nerve-gun. "Back, damn you!" The men froze, staring. Vaulting aboard the vehicle, Boone jammed the gun against the back of the driver's neck. "We're going onto the ramp--out to that Independent ship!" Wordless, the man pressed buttons, swung the steering lever. The carrier jerked forward. More dragging seconds. The great sphere on the ramp looming ever-larger. Boone clipped, "Pull in beside the lift-shaft!" The driver obeyed.