As they approached Bella's house, Edward did u-turn and practically flew to his house. He had bitten Bella, and she was approaching the last stage of Metamorphosis. Edward had to get her out of human range. When the arrived at his house, Edward was already inside getting everything she needed, all the animal blood he could get. He couldn't let her feast on humans, although she would try. When Edward came back out with Carlisle, they carried her frail, soon to be incorruptible body into the deserted room. If and when she woke up, she would feel parched, in which they would have to give her animal blood, so she didn't start hunting humans. She awoke just a couple moments after, and she didn't remember a lot of things that she should have. When her eyes met Edward's she hissed, and he just backed away. Her hiss had sent Carlisle out of the room to get an object symbolizing their love. When he came back, she had already remembered him, and that was just the beginning.