Causal
strong strength
Narrative Connection
How these two moments in the story relate
From
Doctor recognizes nebula threat
S15E17
·
Underworld Part 1
To
TARDIS stalls at the edge of creation
S15E17
·
Underworld Part 1
Why These Connect
The narrative assertion
"K9's discovery of the ion drive signal directly leads to the Doctor and Leela manipulating the TARDIS controls to pursue it, despite the looming threat of the spiral nebula. This sets the trajectory for the entire Minyan encounter."
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.