I wanted to point out couple mistakes in episode 10 (not for the sake of "oh, they're morons" or something, just for clarity):
Firstly, Nana was in the room 702 (Shi Woo says that to Rian), and then the nurse tells Nana that she has to go to 7th floor for the exam. But rooms are always numbered based on which floor they are. So room 702 should already be on the 7th floor.
Secondly (and this is somewhat a spoiler, so people who haven't seen episode 10 yet, please don't read this one), the audition guy tells that Shin Hae Sung made a mistake and then that mistake is shown being done and then covered by erm, forgot his name (Ui Boo or something). But when I rewatched the performance back in episode 9, I saw that at that moment Hae Sung really did that mistake, but so did two other team members, AND Ui Boo (or whatever his name was) didn't do anything to cover it, it just went on.