In Part Four, when Bromden is subjected to electroshock therapy, his narration is overtaken by flashbacks that he experiences as a stream of consciousness:
The machine hunches on me.
AIR RAID.
Hit at a lope, running already down the slope. Can’t get back, can’t go ahead, look down the barrel an’ you dead dead dead.
We come up outa the bullreeds run beside the railroad track. I lay an ear to the track, and it burns my cheek.
“Nothin’ either way,” I say, “a hundred miles....”
“Hump,” Papa says.
“Didn’t we used to listen for buffalo by stickin’ a knife in the ground, catch the handle in our teeth, hear a herd way off?”
The machine "hunching" on Bromden is the machine that is going to shock him. Either as soon as the shock comes or in anticipation of it, Bromden flashes on a traumatic experience he had in World War II. During the war, he and other soldiers were trained to run as fast as they could without looking back when they heard the siren that indicated an air raid, or bombing. Suddenly, in his head, Bromden is not pinned down receiving shock treatment but is instead running away from bombs. The way the coming shock reminds him of the air raids underscores how terrifying EST is for Bromden and the other patients. It feels like being bombed. At the same time, the memory of running from an air raid serves as a kind of escapist fantasy: at least when the bombs came down he had the freedom to run. Now, he can't go anywhere except into his own mind to get away from the shock.
The flashback is not entirely coherent, however. Bromden's mind glides smoothly from the air raid to a hunting trip with his father. It is not clear exactly when the scene changes. Perhaps it is when "[w]e come up outa the bullreeds," but "we" could refer to either Bromden and his father or Bromden and his fellow soldiers. Only when "Papa" speaks is it clear to the reader that Bromden has switched to a different scene than he started with. This kind of indistinct, dreamlike transition between scenes is characteristic of stream-of-consciousness writing. Kesey uses it to demonstrate how Bromden's fear plunges him into free association. Essentially, Bromden's life is flashing before his eyes in a way that does not make narrative sense but that makes perfect emotional sense.