"They went past, but now they're coming back!" cried Kara. "I can hear—"
Birrel kicked the starter and then the gas-pedal, and the sedan shot up the dark asphalt country road like a frightened rabbit.
Kara was looking back, and her voice came clear over the rising whine of the motor.
"They're back there. Gaining on us—"
Birrel glanced up at the mirror and the headlights coming up fast behind. He jammed the gas-pedal down, sending the sedan hurtling past the lighted windows of houses, the black masses of trees. The headlights came no closer.
Kara cried to Holmer, "Use the—" Again, the word that Birrel did not know.
He knew what it meant. The square box in Holmer's lap, the thing that had stricken all in the prison unconscious by its potent vibrations.
Holmer fiddled with the box. Over the roar of the motor, Birrel could not hear it come on. But he looked up hopefully at the mirror.
The headlights stayed right with them.
"No use," said Holmer. "They've got their shields on. They must have known how we did it at the prison."