Statistics of society
Statistical research suggests that an average of 1% of society is populated by psychopaths / sociopaths. Therefore 1 in every 100 professional pilots will have inherent psychopathic tendencies. It is also estimated that up to 4% of those at the top of corporate organisations have such a trait. This is an important fact of life and unfortunately you may not know who these people are until it is too late to do anything about it. As long as humans remain on the flight deck, this will inevitably happen again somewhere, at sometime. Those involved will appear to be 'normal' and it will come as a surprise to those who knew them. I hope not to be a trusting passenger on their last flight.