Shes crazy. She is excessively obsessed with following the book of law. And to her, its at the point where she will kill people like MC who are born/reincarnated with special powers just because they might hurt people/the country. Of course, she is crazy enough to apply it to herself as well. In those last panels she is making the charmed slave physically hurt her with a whip because it emotionally hurts the slave (he loves her due to the charm so it is emotionally painful for him to hurt her), so it becomes punishment for him who doesn have the heart to care for others. And at the same time she is hurting herself physically because it is against the law to violently attack another citizen with excessive use of force which is what she did to him. The thing is, this lady is messed up in the head because she is exactly what she is thinking of people like MC (people with excessive power with the potential to do horrible things), and in her case it is in an actual sense.