I look at this episode in two different ways. The first way is to compare it to the manga, and the second way is to look at just the episode itself. My rating came from the second way.
Vampire Knight had been doing a great job of following the manga, but there was major difference between the manga and the anime in this episode. To begin with, in the manga, the reason Yuki leaves Cross Academy is to do something for the Headmaster, not to chase after Zero. When Yuki is attacked, it is Zero who saves her, not Kaname. In the manga, Yuki discovers Zero is a vampire before leaving Cross Academy. In the anime, she discovers after she returns. These differences really disappointed me, but I can live with them. lol.
As for the episode itself, it was one of the best so far. Even though I already knew the storyline, I couldn't take my eyes off the screen. The vampire attack was really well done except for the fact that it didn't follow the manga. This was really a thrilling episode. I had been waiting for the scene where Zero bites Yuki, and it has finally happened!!! It was just how I imagined it would be. Once again, Aidou is one of my favorite characters. I like how he refused to dispose of his treasures. I hope the rest of the episodes are this good, but follow the manga better. :)