Audio compartido

"Sarah? Is that you?" Elias leaned in, his breath fogging the monitor. The voice that replied wasn't Sarah's. It was a distorted mirror of his own. "Look behind you," it rasped through the speakers. Elias froze. He watched his own reflection in the darkened computer screen. In the glass, he saw the heavy steel door behind him. It was bolted shut. But in the reflection, the door was wide open.