Injection

Because "phenol was... a secret of the camp hospital," and people risked their lives if they revealed it; because prisoner hospital workers realized that to tell the truth to the doomed people would cause them greater pain, and therefore tried to contribute to the illusion of "the injection as some normal administrative and medical procedure"; and because of the universal psychological need to refuse "to accept the idea that life is coming to an end." One could hold to that denial precisely because "everyone had for years [prior to Auschwitz] connected the idea of hospital, doctors, nurses, injections, medical treatment with the struggle for life--and not with murder."
           
--Robert Jay Lifton, "The Nazi Doctors: Medical Killing And The Psychology Of Genocide", p. 259