How embarrassing is it for the Daleks that they are foiled once again by an old man who seems to have spent half of this serial unconscious?
OK, it was actually a group effort.
The Doctor, Susan, and some rebels get to the mine.
Susan and that David guy fiddle with some stuff on the surface that temporarily shuts down the Dalek suits.
The Doctor and another guy climb down a shaft and the Doctor uses his general knowledge of technology to sneak around inside until he finds the control room. Do not call the old man “Doc”.
Ian pulls some wires and stops the bomb the first time, and though he drops down the shaft, he lands halfway down and manages to stop up the hole to prevent the repaired bomb from getting all the way down.
Barbara uses her knowledge of history to confuse the Daleks long enough to learn where the Roboman controls are. And though she and her pal Jenny are caught, the Doctor shows up, and with the Daleks frozen, they order the Robomen to destroy the Daleks and then to take no more orders.
By the by, what was the Daleks’ plan? Well, they were going to blow up the Earth’s core and then propel the planet into space, killing all the humans in the process. That’s just silly.
So, that’s that, right? Well, not really. There’s one more thing.
See, Susan has a thing for that David guy, and he asks her to stay with him. She’s torn between staying and going, but then the Doctor decides for her. He knows her time to stay with him is over, and he closes the doors of the TARDIS, giving her a nice goodbye and…that’s that for Susan. I guess we’ll need someone else to scream like crazy any time something weird comes along.