Causal
strong strength
Narrative Connection
How these two moments in the story relate
From
Doctor hears whispers in forbidden shaft
S4E30
·
The Macra Terror Part 4
To
Doctor and Polly confirm Macra’s parasitic control
S4E30
·
The Macra Terror Part 4
Why These Connect
The narrative assertion
"Witnessing the Macra inhaling gas confirms the Doctor's suspicion that the Macra need the gas to survive and are using the colony as parasites."
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.