Ms. Miki decides to kick the slave in the balls- just for her own amusement. And for those that have seen Ms. Miki in action in the previous clips, you know how entertained she is by all this! She laughs her a** off at the slave's pain & suffering! And she thinks its sooo pathetic that he endures all this for Ms. Kirin! She even taunts him that he "wouldn't want her to give a bad report to Ms. Kirin, would he??"