 Why are the robots incinerating all the living creatures?
The robots were built to serve Man; to do his work, see to his comforts, make smooth his way. The metal killers, tuned to blast any living flesh, would murder them the instant they stepped from the ship! In the movement, his elbow struck the top of a small earthy mound and he was instantly engulfed in a swarm of locust-like insects that beat disgustingly against his eyes and mouth. The planet's double moon had risen and he could see a robot rolling slowly across the clearing in his general direction, blasting indiscriminately at whatever mind impulses came within its pickup range, birds, insects, anything. Powerful as a small tank, the killer robot was equipped to crush, slash, and burn its way through undergrowth.
 Pete built the robots to hunt by following brain waves.
 A radio frequency from Waiamea scrambled the robots' programming.  Pete did not read the directions when assembling the robots.  Pete lost his mind on the journey to Waiamea and programmed the robots to kill everyone and everything.  Pete built the robots to hunt by following brain waves.