There were also people in all the countries of the Reich that helped Jews despite the danger that sometimes killed them as well. They helped physically, which is easier to document, but also (and probably more important) by "misinterpreting", losing and delaying orders. Slowing the process where they could. Many of them will never be known, but their influence could be profound. This DOES NOT EXCUSE THE FIRST GROUP. But just as the terrorists of today, upbringing and religion in combination once again create unspeakable horrors.
So, my friend in Ontario, it is not IF such things can happen. The have and are, all over the world. And it is many times harder to fight cowards in masks who hide in the dark and rejoice in the suicide bombing that will send the bomber to heaven. Look at the records of the Japanese suicide pilots and the damage they caused beyond any "normal" attack while they died for the Emporer. Strongly held belief creates people who act far beyond what we may TRULY understand.