This scene. I can understand why people have said "it's not in character"; though I couldn't disagree more. Mycroft himself has spoken of his distaste for "leg work" and told us that "field work is not [his] natural milieu". He doesn't say why. Laziness is perhaps presumed by the viewer, but - having seen this - I don't think so. We know that Mycroft favours logical thinking patterns and that he believes emotions cloud the judgement. He therefore tries to eliminate all emotion from his thought processes. However THAT DOES NOT MEAN HE DOESN'T FEEL THEM. A stoic is not a psychopath. As humans we are designed, in-built to experience emotion. Mycroft may adhere to principles of stoicism, he may be disdainful and (I would argue) even fearful of strong emotions, but he absolutely has them. Far, FAR more than he would like, wishes to admit or wishes anyone to know about. He wears his Iceman label as a shield. It's his protection. Mycroft has not reached the position he is in without having to make difficult decisions. Has he ordered Loss of Life, imprisonment? Probably. More than likely. But from behind a desk. A shield against emotional attachment. "What about the girl on the plane?" I hear people ask. He was prepared to have that child crash that plane into the sea! If that's not cold detachment I don't know what is! Hmmm, actually he does what he always does (where Sherlock isn't concerned!) he separates emotion and deals with the logistics. And, in a logical sense at least, he's right! If that plane crashes into a town or city then hundreds may die. From a logical perspective, yes. He's no stranger to decisions like this and as long as that person remains abstract to him then that gives him the ability to cope emotionally. He doesn't know this child. He wouldn't want to know this child, because that would make it too hard. Has anyone noticed how he protests the most fervently at the phone calls with the child? He doesn't WANT to be drawn in. Has anyone noticed how at one point of the phonecall he covers his ears? Emotional protection. He's protecting himself from becoming emotionally involved and it clouding his thought process. When Mycroft is handed that gun he is being asked to DIRECTLY kill a person. There is no shield. He is being asked to point that gun at a living, breathing person and pull the trigger. And he is not capable of doing so. He has always KNOWN he isn't capable of doing so and that is undoubtedly the real reason for his dislike of field work. Behind his desk he can do what he does best. Think. Plan. And his hands stay clean. Logically, there is no other choice and he has a man in front of him begging him to shoot him. Logically he knows this, but doing it yourself is very different to giving the order for it to be done when you're safely back in your office.
