gratefulDespite his mantra that everything comes to an end, the one thing the Doctor hates is death. So, because he has to repeatedly decide who lives and who dies, all this guilt keeps piling up and piling up until it's a wonder the man can even function properly, let alone look himself in the mirror.
The worst part is that there really isn't much of a choice in these situations: Gallifrey or the universe, Pompeii or the Earth. One must choose the lesser of two evils and any one of us would make the same decision, despite how desperately awful that choice may be. Tonight, Donna showed him that. She put her hands over his and pushed that lever down right along with him. She took some of the responsibility away from him, some of the guilt.
She gave him the one thing no one else has ever thought to give him. If Rose was a band-aid for the wound caused by Gallifrey's destruction, than Donna is the salve soothing the burn from that band-aid's removal.
I say let the healing begin. And keep those episodes rolling.
