Causal
strong strength
Narrative Connection
How these two moments in the story relate
From
Chumbley’s farewell and Doctor’s urgent retreat
S3E4
·
The Exploding Planet
To
Chumbley sacrifice secures TARDIS escape
S3E4
·
The Exploding Planet
Why These Connect
The narrative assertion
"The Chumbley provides time for the Doctor and his friends to escape and retreat to the TARDIS, directly caused by the order from the Chumbley."
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.