The building has at least three rooms: The courtroom, the bathroom, and the backroom. The backroom is hardly ever used and it's contents are unknown and mysterious. The courtroom is used quite more often and it is where Mia does all of her cases. A small, jail-like area is shown in So Sue Me!, but this could possibly be part of the courtroom.
The backroom is home to a strange, demonic creature. It looks like a wider and larger version of Birdena. The only time the creature has interacted with any of the characters is when it attacked Nut and Mia in The Haunted. It is unknown how they escaped, but both Nut and Mia were safe by the end of the episode.
JailEditA small, jail-like area is shown in So Sue Me!. It is assumed that this is used to contain the losers of the court cases, but it has only been shown once. Nut is shown guarding it. They keep the cells unlocked, meaning it is a very low-security jail.
Sue Lardson, the loser of Sue Lardson vs. Private LaChillz, escapes the jail by communicating with her comrades outside of the jail. Her orders her minion-like assistants to shoot down Nut. Once Nut is shot down, she opens the unlocked jail cell and escapes with ease. This is the only known jail break.