3. Why Did The Moment Take The Form Of Rose/Bad Wolf?
An unpopular decision by Moffat not to have Ten or Eleven interact with Rose, but actually the alternative was rather brilliant. The moment had a consciousness, so it chose the Doctor's conscience. Rose, or Bad Wolf as she was when she saved him from killing everyone in 'The Parting of the Ways', was always the voice of reason in his head, so it chose her. It had all of his life to choose, and it picked the person who helped him not commit genocide again. Clever, eh?