question:  How did Zarwell lose his memories?
context: [p 135 ] By CHARLES V. DE VET monkey on his back Under the cloud of cast-off identities lay the shape of another man— was it himself? Illustrated by DILLON HE was walking endlessly down a long, glass-walled corridor. The truth lurked in some corner of his consciousness, but it was not reached by surface awareness. It took him only a few seconds to push the case into the compartment, lock it and slide the key along the floor beneath the locker. But the fact that they had been expecting him meant that others would very probably be waiting outside. The floor beneath Zarwell’s feet assumed abruptly the near transfluent consistency of a damp sponge. It rose in a foot-high wave and rolled gently toward the far wall. The floor continued its transmutation, and Zarwell sank deep into viscous depths. ZARWELL found himself standing on a vast plain. Zarwell grunted acknowledgment and pushed himself to his feet, apparently unaware that his shirt clung damply to his body. Zarwell was careful not to rest his hand on the flesh searing surface of the stone. The evening meal hour was approaching when he reached the Flats, on the way to his apartment. Zarwell passed a group of smaller children playing a desultory game of lic-lic for pieces of candy and cigarettes. [p 139 ] The next morning when Zarwell awoke he lay for a moment, unmoving. The feeling was there again, like a scene waiting only to be gazed at directly to be perceived. Yet always, when his mind lost its sleep-induced [p 140 ] lethargy, the moment of near understanding slipped away. This morning, however, the sense of disorientation did not pass with full wakefulness. Zarwell moved among them, seldom taking part in the individual clashes, yet a moving force in the conflict . Zarwell was riding a shaggy pony outside a high wall surrounding the stricken metropolis. Zarwell was not the leader of the invaders, only a lesser figure in the rebellion.
output:  Zarwell had his memories removed so he could get out of the revolution business.
options:  A soldier hit Zarwell in the head with the butt of a gun, leaving him with amnesia.  Zarwell was knocked unconscious when a building collapsed around him. He awoke with amnesia.  Zarwell had his memories removed so he could get out of the revolution business.  A bullet grazed Zarwell's head during the last revolution, leaving him with amnesia.