Mistress Bea could not believe that her slave was challenging her and trying to talk back at her. She was angry at that kind of insubordination and she chose to punish him and deal with it as opposed to firing him. She trampled him and she crushed his body with her bare feet and made him endure a lot of pain. That is when she knew what the mistress was capable of.
This mistress likes strong slaves and not weaklings like her current slave. She did not want to let him go on being a weakling. She had to toughen him up and she did. She did it by making him endure her painful trampling and crushing. She jumped on him and crushed him all over including his balls. He tried to cry but she chose to ignore his cries of pain.