Blon promises the Doctor she's changed since they met in London: "There was this girl, just today. Young thing. Something of a danger, she was getting too close. I felt the blood lust rising -- just as the family taught me. I was going to kill her without a thought. And then...I stopped. She's alive somewhere right now, she's walking around this city, because I can change. I did change. I know I can't prove it..." He calmly stops her: "I believe you." She asks whether that doesn't prove she's capable of being better, because she still doesn't understand that from where he's standing, she always was. "It doesn't mean anything," he tells her. She protests, but he's not having it: "You let one of them go, but that's nothing new. Every now and then, a little victim's spared. Because she smiled, because he's got freckles, because they begged. And that's how you live with yourself. That's how you slaughter millions. Because once in a while, on a whim, if the wind's in the right direction...you happen to be kind." This is tenuous, this bit, because what's going on is good, but it's done in a really weird way. It's about problematizing the whole rebirth thing from last week: that the healing of Albion meant the Doctor could choose to be who he wanted to be. The next step of his development should be looking into the mirror that Blon represents and being able to synthesize his darkness with his light, his guilt with his grace, instead of praying for a blank slate and a fresh start every time. That's the next mature step, and maybe it's asking too much for a creature with thirteen lives that they should reach for that. But what Blon says next takes it to a tangent: "Only a killer would know that," and that throws him. She presses: "Is that right? From what I've seen, your happy-go-lucky little life leaves devastation in its wake. Always moving on 'cause you dare not look back. Playing with so many peoples lives -- you might as well be a god." (Which, see above re: her biased viewpoint here, and the Davies obsession with Boys and Girls Who Leave, but still. The other side of the lateral jump is that you're taking advantage of your privilege to do so, and nobody else has to.) The Doctor drops his eyes. "...And you're right, Doctor...you're absolutely right. Sometimes...you let one go." Tearing up in earnest, and pretty heartbreakingly from this side of the screen, Blon looks into the Doctor's eyes: "Let me go." Well played and real.