Alright! So here we are, trying to get this together - the big confrontation.
So they find the TARDIS and realize that they're now in the heart of the Dragon's home. The Doctor is busy scanning bones. In the background, something stirs. The locals arrive, their arms laden with eggs and stand, frozen in terror.
The Doctor picks up a skull, trying to identify the species, saying that the bones aren't that old. More shifting in the background. The locals drop the eggs and then
--> The Locals run away
The Doctor notices the locals running, realizes that he's alone. (Note: Idea - B Story could involve the companions getting lost in the tunnels...?) He pauses, stiffens as he hears a sound behind him. He turns to see:
---> A large CLAW on top of the TARDIS - HUGE DRAGON bears down on him
The 3-eyed creature roars, and rears up, wings spread wide. The Doctor instinctively draws his sonic screwdriver and points it up at the beast -- nothing appears to happen. He fiddles with the settings but gives up as the Dragon lunges toward him. The Doctor decides to:
While running though the caves, the Doctor starts to notice odd little bits of wiring and metallic panels peeking out from the rock. He continues to run, however, as the Dragon continues its chase. As he comes to a fork in the cave system, he heads toward a tunnel that has flickering lights emanating from it. He charges into the tunnel to see that it's a dead end. The Doctor:
-> Discovers the remnants of ancient tech - a giant cryogenic prison cell
He notices that the Dragon has given up chase, in fact, he runs back to the entrance just in time to notice the Dragon storming away. He returns to the metallic cell - this giant chamber and starts to pore over the technology, scanning it, amazed that it's still working -- though only barely. Whatever's keeping this place running, it's finally started to run out of juice. He pieces together that this is a prison cell -- the dragon's prison cell. More importantly:
--> Doctor figures out who the Dragon is and who the aliens were.
But that's something we can get into on Monday when I finish this first draft off all proper-like ;)