So The Master appeared in New Who during the 10th Doctor's adventures and turned the Dr into a cross between Tweety Pie and that pervy old man from Family Guy. Consequently Martha had to walk the earth like Kwai Chang Kane and tell everyone to send the Dr happy thoughts to heal him. Then, when the Master got shot he willed himself not to regenerate. To resolve the mess the Master had made of the Earth he travelled back in time and everything was ok.
Yet Danny Pink gets hit by a car and the Dr can't travel back and say 'look left, look right, look left again'?
I would have preferred a corrupt Romana, that would have been ballsy.