 Why does Quest say he is lucky?
Trella feared she was in for trouble even before Motwick's head dropped forward on his arms in a drunken stupor. The dark man moved in on Trella again as Kregg overtook his quarry and swung a huge fist like a sledgehammer. But that couldn't have been, because the short man wasn't moved by that blow that would have felled a steer, and Kregg roared in pain, grabbing his injured fist. The gravity of Ganymede was hardly more than that of Earth's moon, but the way the man picked up the limp Motwick with one hand and tossed him over a shoulder was startling: as though he lifted a feather pillow. But his ship was drawn into Jupiter and lost.” “It was drawn into Jupiter, but he landed it successfully,” said Quest. I was born and brought up there, and I was finally able to build a small rocket with a powerful enough drive to clear the planet.” “If Dr. Mansard succeeded in landing on Jupiter, why didn't anyone ever hear from him again?” she demanded. It was peculiarly inappropriate, but not unbelievable, that the strongest and most agile man on Ganymede should be a coward. For some reason she decided against telling him that the assignment on which she had come to the Jupiter system was to gather his own father's notebooks and take them back to Earth. Motwick was an irresponsible playboy whom Trella had known briefly on Earth, and Trella was glad to dispense with his company for the remaining three weeks before the spaceship blasted off.
 Quest considers himself lucky that he did not commit murder. He is not a murderer at heart.
 Quest considers himself lucky that Trella is in love with him.  Quest considers himself lucky that he is not actually an android.  Quest considers himself lucky that Asrange did not kill him.  Quest considers himself lucky that he did not commit murder. He is not a murderer at heart.