Narrative Connection
How these two moments in the story relate
Why These Connect
The narrative assertion
"The Doctor's forging of the duplicate key (Episode 16) leads to his ability to secretly repair the TARDIS in Episode 17, despite Polo's attempts to control his actions."
inferred by llm_cross_episode_character
Why This Matters Across Episodes
The longer arc this connection carries
The Doctor's clandestine preparation directly enables his continued efforts to regain control of the TARDIS in Episode 17, where his knowledge and resourcefulness become critical.
About Causal Connections
A directly causes B. The first event sets forces in motion that produce the second. These are the load-bearing connections of plot--remove one and the story structure collapses.