He knew that his only chance to disable the machine was during the pause when its selector changed it from one killing mode to another. But how do you disable a smooth-surfaced turtle-backed machine? Max came at him again, and now its metal hide glistened with a dull green substance which Barrent immediately recognized as Contact Poison. He broke into a spring, circling the room, trying to avoid the fatal touch. The machine stopped. Neutralizer washed over its surface, clearing away the poison. Then the machine was coming toward him again, this time with no weapons visible, apparently intending to ram. Barrent was badly winded. He dodged, and the machine dodged with him. He was standing against the wall, helpless, as the machine picked up speed. It stopped, inches from him. Its selector clicked. Max was extruding some sort of a club. This, Barrent thought, was an exercise in applied sadism. If it went on much longer, the machine would run him off his feet and kill him at its leisure. Whatever he was going to do, he had better do it at once, while he still had the strength. Even as he thought that, the machine swung a clubbed metal arm. Barrent couldn't avoid the blow completely. The club struck his left shoulder, and he felt his arm go numb. Max was selecting again. Barrent threw himself on its smooth, rounded back. At the very top he saw two tiny holes. Praying that they were air intake openings, Barrent plugged them with his fingers. The machine stopped dead, and the audience roared. Barrent clung to the smooth surface with his numbed arm, trying to keep his fingers in the holes. The pattern of lights on Max's surface changed from green through amber to red. Its deep-throated buzz became a dull hum. And then the machine extruded tubes as alternative intake holes. Barrent tried to cover them with his body. But the machine, roaring into sudden life, swiveled rapidly and threw him off. Barrent rolled to his feet and moved back to the center of the arena. The contest had lasted no more than five minutes, but Barrent was exhausted. He forced himself to retreat from the machine, which was coming at him now with a broad, gleaming hatchet. As the hatchet-arm swung, Barrent threw himself _at_ it instead of away. He caught the arm in both hands and bent it back. Metal creaked, and Barrent thought he could hear the joint beginning to give way. If he could break off the metal arm, he might disable the machine; at the very least, the arm would be a weapon.... Max suddenly went into reverse. Barrent tried to keep his grip on the arm, but it was yanked away. He fell on his face. The hatchet swung, gouging his shoulder. Barrent rolled over and looked at the gallery. He was finished. He might as well accept the machine's next attempt gracefully and have it over with. The spectators were cheering, watching Max begin its transformation into another killing mode. And the girl was motioning to him.