As the TARDIS sings, Wilf's Time Lady lowers her hands, and meets the Doctor's gaze. Her son.
Her eyes well up with light, a weeping angel. Wilf stands behind him, and the Time Lady before. The best humanity can offer, and the best of Gallifrey. The soft world, and the hard. They meet in him. There is always a better way. Nothing in us must die to heal the world.
The Doctor points the gun at the Master, telling him to duck, and after a second he grins and does so, and the Doctor shoots the Whitepoint star. Its machine goes up in sparks. The link to Hell is broken. Her hair goes white as she covers her eyes and Rassilon takes aim... And the Master strikes him, with all the electricity in his dying body, sparking and skeletal, blasting toward him. Lit up like an idiot's lantern.
"You did this to me! All of my life! You made me!"
He blasts Rassilon four times, to his knees; they grow faint and vanish, and Gallifrey disappears from the sky.
While on Earth they are rejoicing, and the Master's vanished once again, the Doctor lies on the floor, in a pile of glass.
"I'm alive," he whispers, afraid to break the spell.
"I've... There was..."
He is so joyous, laughing or crying, face against the shattered glass: "I'm still alive." He nearly collapses again, laughing weakly. And hears the knocking.
The dread comes slowly, across his face. One, two, three, four. He closes his mouth carefully, stiffening his lip, finally looking. He is so brave.
Wilf stands in the nuclear bolt, knocking softly against the glass. One, two, three, four.
He waves, embarrassed. "They've gone, then? Good-oh. If you could let me out?"
The Doctor nods, sadly. "Yeah."
("Oh shit," Steve choked, suddenly so angry. "I don't have to! I could stay! I can do what I want!" The cough of an obsolete engine. "Because you need me, you lot need me!" Just embarrassing himself, now. "Power mad? That's the time to go.")
It's making noise. It's been running since the Master brought the Time Lords through. The Gate is gone. The feedback's in overload. "All the excess radiation gets vented inside there," the Doctor says, his voice breaking just a little. "Vinvocci glass. Contains it, all 500,000 rads about to flood that thing."
Wilf tries to be polite, hurrying the Doctor along.