Mistress Jessica felt that she needed to deal with this guy. She was bored and she was looking for a way to have fun at the expense of this guy and that is what she did. The mistress felt that the guy was not doing things the way he needed to be doing and so she had a great time punishing him. She was not even mad at what he had done as it had given her an opportunity to punish him and have fun doing it.
Mistress Julia wanted to trample this loser for her own fun. That is why she chose to use her boots to do it. She did not want to use anything else to do it. The mistress felt that her boots were best placed to crush and trample him the way she wanted. So she tied him up and she crushed and trampled him like she had been meaning to do.