He walked over to the firewall door. On the other side of it was a small chamber where the oxygen and nitrogen of normal air would be swept out before he opened the inner door to go into the inner chamber itself. There was no need for an air lock, since small amounts of impurities in the He-4 didn't bother anything. It was just as he turned the lever that undogged the firewall door that he realized his mistake. But it was too late. The door jerked outward, and a hot wind picked him up and slammed him against the far wall. There was a moment of pain. Then--nothing. * * * * * _There was something familiar about the man who was turning the wheel, but de Hooch couldn't place it. The man was wearing a black hood, as befitted a torturer and executioner._ _"Idiot," said the hooded man, giving the wheel of the rack a little more pressure, "explain the following: If a half plus a half is equal to a whole, why is halfnium plus halfnium not equal to wholmium?"_ _Stretched as he was on the rack, de Hooch could not think straight because of the excruciating pain._ _"Because a half is eight point two eight per cent heavier than a hole," said de Hooch._ _"You are an idiot, none the less," said the torturer. He gave the wheel another twist. De Hooch wanted to scream, but he couldn't._ _"Try again," said the torturer. "What is a half plus four plus four plus four plus four plus--"_ "Stop!" _screamed de Hooch_. "Stop! _Stop at the osmium!_" _"Ah! But it_ didn't _stop at the osmium," said the hooded man. "It went on and on and on. Plus four plus four plus four plus four plus four--until there were so many plus fours in there that the place looked like an old-fashioned golf course."_ _"My legs hurt," said de Hooch. The man was no longer wearing a hood, but de Hooch couldn't tell if it was Willows or himself._ _"We will all go together when we go," said the man._ _De Hooch turned his head away and looked at the ceiling._ And he realized that it was the ceiling of the antechamber. "My legs hurt," he repeated. And he could hear the hoarse whisper inside the helmet. He realized that he was lying flat on his back. He had been jarred around quite a bit in the suit. He wondered if he could sit up. He managed to get both arms behind him and push himself into a sitting position. He wiggled his feet. The servos responded. He hurt all over, but a little experiment told him that he was only bruised. Nothing was broken. He hadn't been hit as hard as Ferguson and Metty had been. "Willows?" he said. "Willows?" There was no answer from the earphones. He looked at the chronometer dial inside his helmet. Oh two forty-nine. He had been unconscious less than ten minutes.