Episode Four begins with just about the most heroic, violent act ever committed by a Doctor in order to save his companion from certain death, in one the most memorable scenes of the entire story. As we pick up the action from the Episode Three cliffhanger, Sarah is about to have her arm infected by the Krynoid pod, which is about to sprout. The Doctor, seeing this through the sky light, jumps through the glass, knocks over Scorby, breaks a chair over his back, then pulls a gun on Chase, who says dryly, "What do you do for an encore, Doctor?"
The Doctor's reply? "I win!", as he pushes aside another guard, grabs Sarah, and makes a dash out of the room. I have seen this scene thirty times and I punch the air harder each time I see it. The Doctor gets his own comeuppance, though, as Scorby catches him investigating the exploded pod, and, in an even more violent scene, really roughs The Doctor up by throwing him repeatedly into some garbage cans before showing him the massive composter that Chase has installed in his house.
And yet, as awesome that this story continues to be, the one thing I still notice every time I watch this episode, sometimes more than anything else, is the scene where Sarah rescues The Doctor in the nick of time before her friend is about to be ground up in the compost machine. Tom Baker turns over, tries vainly to wipe his nose, but fails utterly to stop the large dollop of snot that drops from his nose soon after. The sequence is so flawless up until that point, though, that I can see why Douglas Camfield didn't order a retake.
The final shot of this episode, that of a cheap rubber Krynoid costume bouncing towards the camera, has been mocked a few times, including on one notable 2|Entertain DVD documentary, but it doesn't look that bad, and the super rare night shoot is shot fantastically well on glorious videotape by director Camfield's team.