In fact, the Doctor finally admits, every time he opens the TARDIS doors, he changes history. After all, the TARDIS was designed to observe history. That’s why it has a scanner and chameleon circuit – so it can disguise itself in a given time period and simply watch in silence. The biggest aspect of the Doctor’s renegade nature is not that he runs around the universe willy-nilly – it’s that he ever leaves the TARDIS.
