Hitting Level 30 has lost a little bit of its shine in the current game. Back at launch, Level 30 meant that you were halfway to the level cap, and that while each level would require gradually more experience, you'd be over the midway point. However, you were still 10 levels away from your ground mount, and were usually sick of walking everywhere. Now, you aren't even close to half of the level cap. For a brief time after Burning Crusade came out, the mount requirement was lowered to Level 30, but now it's 20. So while it's fun for the achievement screen to pop up as it does every 10 levels, you don't really get a whole lot out of it, save for a fun new skill for your class.
Back in the Scarlet Monastery, the next wing that players usually tackle is the library. Upon entering, you are placed in an open courtyard named the Huntsmans Cloister, named for the boss in the area who controls four hounds.
You make your way back into the building, through the treasure rooms and library, and find Arcanist Doan, the main boss of the wing waiting for you. Being a mage, he can turn anyone in your party into a sheep, and also disrupt your group with fire, making this one of the earliest fights that isn't a straightforward kill...you actually need to pay attention to what's happening.