Steadily, accurately, Sim began to cut away a river bed for the storm waters to flow in. The night was turned to day by its hungry eating.
The return to the cliffs was to be carried out by Sim alone. Lyte was to remain in the ship, in case of any mishap. The trip back seemed, at first glance, to be impossible. There would be no river rushing to cut his time, to sweep him along toward his destination. He would have to run the entire distance in the dawn, and the sun would get him, catch him before he'd reached safety.
"The only way to do it is to start before sunrise."
"But you'd be frozen, Sim."
"Here." He made adjustments on the machine that had just finished cutting the river bed in the rock floor of the valley. He lifted the smooth snout of the gun, pressed the lever, left it down. A gout of fire shot toward the cliffs. He fingered the range control, focused the flame end three miles from its source. Done. He turned to Lyte. "But I don't understand," she said.
He opened the air-lock door. "It's bitter cold out, and half an hour yet till dawn. If I run parallel to the flame from the machine, close enough to it, there'll not be much heat but enough to sustain life, anyway."
"It doesn't sound safe," Lyte protested.
"Nothing does, on this world." He moved forward. "I'll have a half hour start. That should be enough to reach the cliffs."
"But if the machine should fail while you're still running near its beam?"