Mistress Alice was fed up with how noisy this guy was. She had tried to ask him to take it a notch down but he did not. And for that, she had to teach him a lesson. She chose to make sure that she humiliated him in a way that he had never been before. That is why she did what she had to do to. He got the message and changed.
Mistress Alice needed to trample this loser and she had to do it in a way that he would never forget. That is why she chose to dominate him and to teach him a lesson that he had never been taught before. The mistress did not care how painful it was as the guy had to learn his lesson and learn how to be consistent. The punishment worked as it was intended.