Of course you can join, Pudding. ^^ 

No, they're at the school. xD I suppose he can stay out there and come back to the dorm eventually, but that'd be kinda boring.

I'll take a minute and explain the layout of the dorm for Knight. ^^

The Iwatodai Dorm is four floors, plus the roof. 

The first floor is the lounge. Once you enter, you come across the sign-in/out area to the side. In that area, there's a computer, and a board where announcements are posted. On the other side of the door is a lounging area. Thee are three couches arranged in a "U" shape with a table in the middle. On the other side of the room is the dining area. There is a fridge next to a bar that has drinks and food. This floor is where everyone is at at the moment. 

The second floor is for males. There's a little sitting area off to the side with a table, some chairs, and a vending machine where you can buy drinks. Beside that, there's a hallway where the rooms are. This floor is off limits to girls. (You can pass through on the way to the third floor, but you can't stay here.)

The third floor is for females. The setup is exactly the same. Again, this floor is off limits to boys. 

Next is the fourth floor. There is an open space with two doors. A set of double doors leads to the command room. On the other wall there is a single door. That is the chairman's room. Another set of stairs leads to the roof. For now, the fourth floor is off-limits.