Ballard leaned far over the rough edge of a circular pit, directing the heat radiation beam that melted the foundation plastic smoothly over the walls. He couldn't spare the time to turn his head and watch Walton, but he could follow the other's progress in welding the framework of the blinker tower by the irregular breathing and clanks and buzzes coming through his earphones. He listened to Walton's motions with an automatic alertness developed over six long weeks of tension—ever since the finding of the rotenite nuggets on the second of the light-marker asteroids. The rotenite represented enough wealth to make them among the richest men in the solar system. Or one of them—the richest. That was what Ballard was afraid of.
Suddenly the clanks and rustles stopped, and Walton's voice muttered: "Must have left the number three flux; better go back for it."
"What?" Ballard caught himself asking rhetorically, apprehension flooding through him.
"I said I left something. Have to go back and get it." There was a faint tremor in Walton's voice.
With a hard calm he wouldn't have recognized six weeks ago, Ballard considered the consequences of making an excuse to go with Walton. But the excuse would destroy the pose of innocence he'd so carefully acted since his first suspicions of Walton's intention. And he could be wrong. No sense in antagonizing Walton, particularly with the frayed condition both their nerves were in. "Ok," he grunted. "Bring back another 5R bit; this one I've been using chitters."
There were the sounds of Walton bounding down towards the ship in the peculiar dancing glide demanded by the low gravity. Methodically, without looking up, Ballard continued his job, following Walton with his earphones. Only when the foundation fill was laid would it seem natural for him to stop working for a moment and go to the ship.
Gradually, layer on layer, the plastic melted, coated the walls and hardened. He heard Walton reach the ship, then there was a slight ringing noise as the man touched his key-magnet to the airlock. As Walton entered the lock, his mike registered the pressure of air by suddenly picking up all the sounds of the ship; the throbbing of the generators, the intermittent rush and sigh of the air conditioner, and the close curved walls echoing back the scrape of his shoes on the locker room floor.
Four minutes to go. Ballard finished melting the plastic onto the walls, resisting the urge to hurry and risk botching the work. Walton had no reason to kill him—except for the rotenite. And since its discovery, Walton had shown nothing but a surface friendship covering a hidden hatred and fear that was growing into surreptitious maneuverings towards murder. But with a pretense at normality, Ballard hoped Walton would get over his obsession and forget it, never knowing that he'd seen anything suspicious. And meanwhile Ballard had only to stay out of the way of accidents without seeming suspiciously careful.
He added the last necessary layer of plastic, switched off the heat beam and stood up. There was no sign of motion around the Minnow. Walton had not come out, but Ballard's earphones continued to pick up Walton's nervous, irregular breathing.