Uchi no Maid ga Uzasugiru! Temporada 1 Episódio 12

Washiwashi and Yui end up going into Mishas very special room that no one is allowed to enter. Misha finds out that someone entered the room without permission and Tsubame immediately takes the blame, saying that she was the one who entered the room. Misha ends up going into the room and locking herself in. Yasuhiro gets a call about this and comes home. Why doesnt Misha want anyone to ever enter that room?