“Goodness had nothing to do with it.”
Clara and the Doctor resemble each other, in their love for adventure and saving the world, in their cleverness and recklessness, and in the chaos and destruction they’d be wiling to unleash for the other. For two people who are so similar, a story holding up a mirror between is a powerful thing.
Realisations can be discomforting, painful even. Clara slips into the Doctor’s role and the Doctor meets someone who calls herself by his name, who does not truy fit into this world in spite of looking the part, who readily chooses lying as a way to achieve her aim, who moves on after witnessing a death with no time for grieving. What does being the Doctor mean? He leaves Clara standing there, staring ahead, her expression puzzled.
Clara looks into a face which has gone through unimaginable terror for billions of years, she demands to know why, and is met by her own reflection. “Why would you even do that to yourself?,” asks the girl who
jumped into the Doctor’s time stream to be torn into a million pieaces.
“I have a duty of care, you know what that is?,” a teacher explains in another time, in another place. Wouldn’t she have done the same here, chosen the path that horrifies her? Would goodness have had something to do with it?