I think that it’s stuff like this that really shows that we are not quite the free-will-based animals we think we are. We spend most of our lives priding ourselves on the choices we’ve made. Claiming that we are different than those who commit horrible acts of violence. However it seems that when faced with what should be an opportunity to stand up for a fellow human being, we fold like a house of cards if even a small amount of psychological pressure is applied correctly. As Scott Adams would say, we are all just moist robots.