Trivia / Doctor Who S5 E4 "The Enemy of the World"
Acting for Two: Patrick Troughton plays both Salamander and the Doctor for this adventure. Considering the only difference between them is a hair style and costume and accent, Patrick Troughton puts his heart into making those two completely different.
The chase scene in the first episode originally took place in a crowded holiday resort. This was changed due to logistical difficulties.
Initially, it was planned that the Doctor and Salamander would meet more than once, but due to the technical complexity, there was eventually only the one confrontation scene, at the story's climax (utilising editing and a split-screen technique).