Responses
Because since Lucaon keeps claiming he isn't exactly fond of servants, if he gets caught he might blame Kyon and/or end their "relationship", and/or the other servant guy might think Kyon is being abused (due to the torn clothes and Lucaon's "cold" attitude and stuff). Either way, it'll open the door to a lot of drama.

Does it really matter if he gets caught playing" doctor" with his servant? I mean they all seemto be doing it so i was wondering why it needs to stay such a secret?