Test For the Pearl

Together, the Earthman and the Jovian outfought and outwitted the prison guards, the Venusian jungle-hell, the cunning Chameleon men. Together, they were invincible. But at the Test for the Pearl they divided....
Far off in the steaming Venusian jungle, a band of the Chameleon men halted, lifting their mottled faces in the direction of the sound. Closer in, a four-man jungle patrol of Earthmen broke as one man into a run along the trail, their swift-moving bodies swishing the clouds into ragged streamers.
At the edge of the viscous river circling the island an armed guard slipped on his infra-red glasses and began searching his area carefully, his special light traveling slowly along the river and its near and opposite banks.
On the island, only a few yards from the high, thick walls of the Interplanetary Prison, a patch of ground, approximately eight feet by five quivered once—and was still.
The deep-throated roar of the escape siren was thunderous. It carried for scores of miles through the steamy atmosphere of the planet, alerting both natives and Earthman patrols to a successful break from that most fabulous of prisons—The Hole.
Behind the oxygen mask he wore, lying under a foot of the thick spongy soil of the planet, Jarl Gare wiggled his itching body and chuckled.
He nudged Waltk, the huge Jovian who lay beside him. Don't get restless, now, he mumbled through the mask. We have hours to wait. And somebody might spot this patch of ground if you keep wriggling.
The Jovian grunted, wriggled again, and then was quiet.
Men have escaped from The Hole before, Jarl Gare muttered, but they were always caught before they got to the pearl-beds. Waltk's body and my brain will get us through.
He envisioned one of the huge Venusian pearls—so rare and so precious on Earth that it could buy a man's freedom, even from a murder charge.
Jarl Gare fell asleep, dreaming of a bauble as big as his head.
He was awakened by a nudge. It is night, Waltk grunted. I smell it.