Causal
strong strength
Narrative Connection
How these two moments in the story relate
From
Doctor and Susan assess the drainpipe climb
S2E2
·
Dangerous Journey
To
Susan insists on leading the climb
S2E2
·
Dangerous Journey
Why These Connect
The narrative assertion
"Determining that the pipe may lead to Ian and Barbara drives the Doctor to want to climb the pipe to try and find them."
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.