Causal
strong strength
Narrative Connection
How these two moments in the story relate
From
Sphere vanishes into invisible ship
S17E23
·
Shada Part 3
To
Discovery and entry of invisible spaceship
S17E23
·
Shada Part 3
Why These Connect
The narrative assertion
"Witnessing the sphere vanish into an 'invisible spaceship' immediately leads the Doctor and his team to search for and locate the entrance—a red carpet leading to a ramp—into the vessel. This sets up their fateful entry."
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.