JG: Now. Big, big, big moment coming up for the Doctor, here.
JG: Big, big moment. What— Talk us through this. Choices made.
DT: Oh, dear.
JG: How dark did he go? Did you go, as the Doctor.
DT: Well. I think it was important that the Doctor was caught by Donna here. I think it was important that the Doctor saw that he could lose control. That in this kind of post Rose state, he’s perhaps not as balanced and in control as he would wish to normally be. And so the carnage that he’s about to create… Basically, I suppose what’s important story-wise is that the Doctor realizes he shouldn’t be on his own. Even though all his instincts at the moment are telling him to be.
JG: Yeah. And it’s an extension on “No second chances”, isn’t it? It’s a darker… No second time— That ruthlessness. That clarity…
DT: Absolutely. Which comes from a fairly dark place. And I think Rose had helped him come out of that dark place, and perhaps he’s rediscovering it a little bit here. And that’s not entirely healthy.
- David Tennant & Julie Gardner - The Runaway Bride commentary