 After realizing his situation after the crash, why did Rolf laugh?
Sisko Rolf's stocky body was a blur of motion as he cut the rocket jets, doused the twin searchlights, and switched over to the audio beams that served so well on the surface when blind flying was in order. Rolf swung the lax controls over hard as the bursts of fire revealed a looming barrier of stone dead ahead, and then he felt the tough skin of the flyer crumple inward. Somehow Rolf found the strength to wrap his fingers around the control levers and snap on a quick burst from the landing rockets. The ship struck; split open like a rotten squash, and Rolf felt himself being flung far outward through thick blackness. There was light in the narrow pit in which he found himself, light and heat from the yet-glowing debris of the rocket flyer. Toward this barrier the spinner bore him, and Rolf was content to let it move in that direction—from the heights of the wall he could scout out the country beyond. The spinner had slowed its speed; it seemed to Rolf that he must be falling free in space for a time, but the feeble gravity of the tiny world tugged at him more strongly as he neared the wall. So slowly was the spinner dropping that the blackened desolation of the other hemisphere came sliding up beneath his boots. Deftly Rolf nested the spinners again in their pack before he set out toward the heaped-up mass of stone blocks that was the wall.
 He was facing certain death
 He was facing certain death  His laughter was caused from the thick air  He was satisfied with their journey.  He was happy to be away from Garmon