also worth noting there's not a single "survivor" account that mentions the effects of a non-lethal dose of cyanide. cyanide isn't either/or. cyanide doesn't either kill you or let you walk away unscathed. no "survivor" account mentions nausea, dizziness, fainting, or the cognitive impairment a substantial but non-lethal dose would cause.

all of the inmates that handled the bodies would have exhibited the effects of cyanide exposure. and if the guards/facility handled the gas the way the "survivor" accounts claim, there would have been noticeable symptoms and even ancilliary deaths among staff.