He put a knee on the other's chest. "Who are you?" he demanded.
No answer.
"Why'd you send out an SOS?" Carter demanded.
The other man glared coldly at him without replying.
Carter pulled him to a sitting position and slapped him, twice, hard. "Answer me! You're from the Vanguard expedition, aren't you?"
"Yes." The voice sounded steely, metallic.
"Then why'd you jump me? I picked up your SOS and came down here to rescue you! Answer me!"
"You'll know the answers soon enough."
Carter shook his head angrily. "I want to know right now. Where are the other members of the expedition?"
"They are here. They are all safe."