Causal
strong strength
Narrative Connection
How these two moments in the story relate
From
Scarlioni reveals his fractured selves plan
S17E8
·
City of Death Part 4
To
Scaroth unveils his plan before fleeing through time
S17E8
·
City of Death Part 4
Why These Connect
The narrative assertion
"Scarlioni/Saroth's revelation of his grand plan to Romana sets up his later reveal of his true form and the activation of the time machine to the Doctor, showing the escalation of his villainy and the consistency of his goal."
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.