Lady Karame is not a mistress you want to mess with if you can avoid it. This guy was her competitor and he managed to piss her off by using underhand tactics to try and beat her. She was fine being beaten fair and square but not through underhand methods. When she realized that, she punished him cruelly. She brutally trampled the guy using her boots and she even made him lick the dirty soles. She made sure he made amends.