Well, I-hang-around-in-doorways, if a nice chap with SS runes on his uniform had said to you "Open ziss tin marked Zyklon B und tip it down into zat room marked 'Showers' ", would you have replied "Jawohl, Herr Obersturmbahnfuehrer, zu befehl!" and obeyed such an order without question?
Hopefully not.