Goddess Mia did not really want to punish her slave but she wanted to scare him. He was new and she felt that she had to scare him so that he learned not to piss her off. He had to do things her way and is why she told him he would lick her feet clean if he messed with her or he ignored her instructions. She even described everything in detail and that is how he got scared.
Goddess Mia wanted to show this guy that it was wrong to mess with her and so she used her foot fetish to stomp on him and teach him that she was out of bounds when it came to messing with her. But the mistress had to find a way to deal with the guy and she did it with her boots as well as with her cigarette by using him as her human ashtray.