And Flint saw he was only wasting time. He leaped forward and caught the man full in the face with his fist. The blow sprawled the patrolman backward against the controls. Before he could get up, Flint was on him again, struggling for his gun. If he could get out of here, get that police plane-- He got his hand on the gun. Twisted. But it had taken too long. He felt the hard jab of one of the patrolmen's pistols against his back. "Get off him!" Flint stepped back slowly, hands hanging limp, ready for the slightest opening. But it didn't come. The big man got off the controls, holding his hand over a nose that was probably broken. "Put him in that air lock," he ordered. "Give him enough pressure to cave his ribs in!" The inside door was open. Flint was shoved into the lock. The door clanged shut behind him. * * * * * Around the wall in the narrow air chamber was a line of tiny holes. From these came a shrill hissing like a nest of snakes. The pointer of the pressure gauge on the wall trembled, then slowly moved across the dial. The chamber was six feet high, three feet wide. The air holes were near the ceiling beside Flint's ears. But he didn't stand there listening to the rising pressure. A moment ago, one of the patrolmen had passed through here. Immediately, he tried the other door, the one leading outside where the police ship was hooked on, but it was locked now. The doors of a space-ship's safety chamber worked together. When one was locked, the other locked automatically. But when one door was unlocked, the other was also unlocked. He leaned against the outside door, his mind racing. If he could stay conscious against the air pressure--if he could slip through this outside door when they opened the inner one--he'd be in the police plane-- The pressure gauge was calibrated in pounds. With each mark the pointer climbed, he shuddered. He jammed his fingers into his ears, closed his eyes, swallowed constantly. His face turned white under rivulets of sweat. His shirt was quickly soaked through, his big arms wet and glistening. Swiftly he felt his strength leaving him. The pointer on the gauge quivered at the hundred mark, slowly climbed higher. Flint found his knees sagging. His heart pounded with the exertion of standing up. His body had turned to lead. And in his mind was the terrible fear that he'd black out completely, be lying there on the floor when the other door unlocked and gave him his only chance. But he _couldn't_ black out! He had to keep on his feet! He was Karen's and Greeno's only chance. The pointer stood at a hundred and fifty. His ribs felt as if steel bands were being tightened around his chest. He couldn't breathe. He knew he couldn't stand much more. He turned his head toward the inside door and with all the lung power he could find yelled, "Let me out! I'll talk!"