Doctor Who: 10 Times The Doctor Was The Bad Guy
The Doctor's hand spare hand finally fulfils its purpose in Journey's End, the close of the fourth season of the revival. The DoctorDonna is born, creating another copy of the Tenth Doctor. While this initially seems like a fantastic, eleventh-hour means of rescuing The Doctor and his companions, it comes with a huge cost.
Donna Noble is able to stop the Daleks and Davros thanks to the Human-Timelord Metacrisis, accessing their controls and spinning them all out of control. While both the Tenth Doctor and his duplicate join her in this task, it is the duplicate who takes the mantle here though.
While the Daleks are a hugely destructive force in time and space, the Doctor himself stopped short of wiping them out before they even had a chance to begin, back in Genesis of the Daleks. The duplicate feels no such restraint. He initiates a power surge that wipes every single Dalek connected to Davros from existence. While the reasoning behind the act was to save the universe, mass genocide is rarely a viable option A. As punishment for his actions, the Duplicate Doctor is locked away in the parallel universe. Don't feel too bad for him though, as he finally got to live out his days with Rose Tyler.