There are two kinds of doctor: those who have been involved in a serious incident and those who will be involved in a serious incident at some point in the future, sometimes as a result of their own error, and sometimes due to the circumstances under which they must carry out their work. It is usually a combination of both, and subsequently the doctor almost always feels responsible for the unintended harm caused to the patient.
It is difficult to discuss this kind of experience with others. Openness requires courage, but also an environment that is prepared to listen without prejudice.
(Thanks to Howard for the lead!)