It's horrible, but sometimes is unavoidable. To protect the sheep, sometimes you must kill he wolves. If I have to choose between the life of a innocent child and a rapist pedophile, for example, I would choose nthe child with no hesitation. How about killing a single dictator that can kill thousands of people? Sometimes you need to do a single math... There are people who can deal with that, and accept that reality and others who don't. Mai had the skills to do what was necessary, but not the mental fortitude tô endure it. And that's why she broke.