In the mood for a hypothetical?
You are an extremely skilled and talented medical doctor. There is a very ill and very evil dictator who has come to your hospital to receive treatment from you. If/when he is treated and well, it is certain that he will go back to his home country and murder thousands of innocent people. The government’s hands are somehow tied.
Would you feel a duty to do your job?
Would you try to kill him yourself?
Would you treat him?