Wilf wanders about, in love with space, while the Masters down below shut off their means of returning by shooting a big machine, and then -- since the Master has the entire nuclear power of the Earth at his disposal -- the Doctor sonics their spaceship dead. This pisses the awful Vinvocci off, but Wilf's sure that the Doctor's got a better plan. "I know you, though. I bet you've got a plan, haven't you? Eh? Come on!" Adorable: "You've always got a trick up your sleeve. Nice little bit of the old Doctor flimflam, ha-ha-ha, sort of thing? Eh?" The Doctor just stares. "Oh, blimey."
They float, for a long time. Night has fallen. The Masters gather, and across the world they begin to listen. The drumbeat that distracts them and drives them mad, the untempered schism in us all, becomes their focus. And they find the source.
"The signal has been sent," the Time Lord reports to Rassilon. "A simple task of four beats transmitted back through time, and implanted in the Master's mind as a child." This links them to him, across Eight's Timelock, and then Rassilon somehow gets a tiny simple diamond across the link, a Gallifreyan Whitepoint star, plucked from his staff and tossed through time.
THREE: A Girl
The Doctor sees a burning, falling star in Earth's atmosphere down there; the Masters go running for it, and when they see what it is, they begin to exult. He raises his eyes to heaven and nearly weeps, but laughs instead. The skull beneath his skin growls and burns.
Wilf wanders the Vinvocci ship, and is once again surprised by his Time Lady messenger. "I think I'm lost," he says, and she smiles: "And yet you are found. Events are closing. The day is almost upon us. But tell me, old soldier. Did you take arms?" He shows her the gun and she nods. "This is the Doctor's final battle. At the end of his life, he must stand at arms, or lose himself and all this world, to the end of time." Wilf knows the Doctor carries no guns; how he hates them. "Who are you?" he asks, and she smiles sadly. "I was lost. So very long ago." And she is gone again.