Third Doctor (Dead on Arrival)

A version of the Third Doctor existed on an alternate Earth that the Jo Grant of N-Space was once accidentally sent to. After mourning the death of his own version of Jo, not knowing that she was in fact in a coma due to the N-Space Jo's arrival causing her life force to disappear, he returned to UNIT HQ, where he detected a hole in the space time continuum, and somebody on the other side trying to get through, unaware that it was his N-Space counterpart. He fell into the same coma as Jo when the N-Space Doctor managed to break through to retrieve his Jo, and awoke after the two managed to return to N-Space and return the life forces.

He was mostly identical to his N-Space counterpart apart from, according to his counterpart, being "a bit vainer". (COMIC: Dead on Arrival)