"On the contrary," said Archer quickly, "since that borrowed helmet might not make any difference now, you need me worse than ever. That is, unless you trust each other implicitly." He spoke the last few words with slow emphasis.
For a long moment, the gun held steady, then it lowered a little. Stokely gestured with the other hand.
"Take it off," he said harshly, "and I'll hear what you have to say. I'm not promising anything, though. For instance—why should I trust you?"
Archer removed his head-globe, admitting the outer air. It was cold against his face, and so dry by comparison with the humidified air of his pressure-suit that it caught in his throat as he breathed. He left his headset on for communication with Stokely.
"Maybe you won't have to," Archer answered steadily. "I have a plan that might work in spite of our low regard for each other's veracity. But—in case it doesn't—you'll be better off if you take off that globe."
Stokely sneered. "You'll have a hard time selling me that idea!"
"I don't think so, when you see the point. You're forgetting that in this case, a false cure is just as deadly as the disease. I don't know just how full of the virus the air is hereabouts, but as far as either of us can tell, you may be cutting down your chances of getting infected. Evans' chance, and mine, with full exposure, will be four out of five. That means if we can't find out for sure whether we have it, we can take an injection and be 80 percent sure of being right.
"How sure can you be?"
Stokely's face set in a grim mask as the realization sank in. He removed his globe and set it out before him on the ground. Again the gun raised to Archer's chest.
"Okay, bright lad, you put it on!"