There is a story going around the internets about a 22 year old woman who was gangraped by fellow KBR/Halliburton employees in Iraq. She was then thrown into a shipping container, refused medical treatment and told not to tell anyone. She only escaped because a sympathetic guard let her use his cell phone to call her dad.
Amanda wonders why the guard didn't do more. I don't. I know that it takes a very special type of psychology to be a "helper" in these cases where MOST people who are told they have a job to do would follow orders, even if those orders are morally repugnant. Study after study has shown that people who are doing a job will commit heinous act, the most notables being the Milgram experiment and the Stanford Prison Experiment, if it is part of their job. In the Stanford experiment only one person out of over 50 objected to the way the prisoners were being treated.
There are some specific traits to "helper" types, while there are no outstanding traits to those who would inflict pain. Helpers generally have a parent who was highly ethical and held them to high ethical expectations, they usually come from some kind of marginalized group like a religious minority and they have an adventurous spirit.
For everybody else, doing a job that you have been told to do is more important than how you feel about the job. There is a responsibility trade off. The actors give up moral responsibility, they are just doing what they are told, and take on the physical responsibility of the actual work of inflicting pain. When you give people in a group this kind of work, they are even less likely to question it than if you give it to an individual.
So while we may be horrified (I certainly am) at the behavior of the KRB men who raped this woman and their fellow employees who prevented her from getting help, it is not surprising. MOST of us would behave the same way in the same circumstances. And that is probably the saddest statement on the state of humanity that there is.