Shooting was in fact more humane than the ghastly experience of herding two hundred men, women an children naked into a space hardly enough for 150. The lights would then be turned off, the posion gas pellets poured in from a glass enclosure up above so they could watch the victims suffocating under extreme terror and agony. The victims would die, their bodies climbing over each other struggling to get some air that remained. After several minutes the doors were opened, the dead bodies covered with feces were removed and ended up in the crematorium.
The ruse of using the "showers" was not a money saving device but one in which huge groups of people could be kept calm, unsuspecting of any danger about to befall them.
My intent was to highlight cruelty of Mr. Heller’s “take a pill and die” recommendation. “Efficient and humane” was intended as sarcasm.