Im working on the next installment of one of my short stories and, in it, there is an FBI agent who is a high-ranking official. One of his very best friends is a mercenary/criminal mastermind type of guy. One of the member's of the criminal's mercenary group is taken hostage by a gang and he turns to the FBI agent for help. The agent responds that he is willing to help get the hostage back, but he has a favor. That favor is for the mercenaries to assassinate a foreign leader that is visiting the UN in New York City. What I'm wondering and what I could use some advice on is how to sort of justify this FBI agent going against what he has been trained to do and asking these mercenaries to commit this unthinkable act? I guess. Any advice and help would be great for me.