"I can believe that. Most people have done good and bad. And very often the ones with the greatest capacity for bad can also do a lot of good." The Doctor looked past Jack, absently turning a lever of the console. "And the other way round." He ran a hand through his hair and ended up first tugging at it and then rubbing his earlobe between two fingers as he looked at Jack. What a question. Who was he to make such decisions? It was so tempting to make these decisions. But make them properly. Go back in time and keep John from ever becoming the man who'd end up disappointing Jack again and again.

"...I don't know, Jack." What would he do? What would he have done with the Master? What would he do if the Master came back, as he was starting to believe? "I don't know what I'd do."

He let out a slow breath and shrugged. "You have your team to think of. Ianto."