"The keys!" Villanowski panted. "Y has them."
Nadia opened her mouth to scream again.
"Don't." Gavin pointed the dart-gun straight at her open mouth. Nadia shut it.
The factor was writhing on the deck, but Y lay like dead. Gavin found the keys and released Villanowski.
"The engine room," he cried, "we've got to reach the engine room."
"Take Y's gun," said Gavin. He turned on Nadia. "Come along. We can't leave you here to sound an alarm."
Nadia's lips were bloodless. She moved stiffly between them, Gavin's dart-gun prodding her gently in the spine.
They reached the engine room without being discovered and disarmed the startled guard. Villanowski whistled a bar in C sharp and then said, "Open sesame." The door in the steel bulkhead swung soundlessly outward.
There was a faint grin on Villanowski's homely face. "Sound waves set its mechanism in operation. I read a story when I was a youngster—Ali Baba and the Forty Thieves," he confessed. "When I built the lock I couldn't resist designing it to respond to those vibrations."
The ship rocked slightly.