"The acceleration tube of the ultracosmotron runs due north of here for two miles underground. The guard at the other end won't be expecting anyone to be coming from the inside of the target building. If Bern plays his cards right, he can get away."
"Can't we phone the target building?" the FBI man asked.
"No. We shut off all the electrical equipment and took down some of the wires so we could balance the acceleration fields."
"Well, if he's on foot, we could send a car out there. We'd get there before he does. Uh ... wouldn't we?"
"Maybe. But he'll kill himself if he sees he's trapped." That wasn't quite true. Bern was ready to fight to the death, and he had a heavy pistol to back him up. MacHeath didn't want to see anyone killed, and he didn't want stray bullets flying around the inside of that tube or in the target room.
MacHeath and the FBI agent piled out of the elevator at the bottom of the shaft. Dr. Roger Kent was standing at the head of the stairs that spiraled down to the gun chamber. Dr. Kent knew that Bern had gone down the stairway, but he didn't know why.
"He's our saboteur," MacHeath said quickly. "I'm going after him. As soon as I close the door and seal it, you turn on the pumps. Lower the air pressure in the tube to a pound per square inch below atmospheric. That'll put a force of about a ton and a quarter against the doors, and he won't be able to open them."
Dr. Kent still didn't grasp the fact that Bern was a spy.
"Explain to him, Morgan," MacHeath told the Federal agent. He went on down the spiral staircase, knowing that Kent would understand and act in plenty of time.