Causal
medium strength
Narrative Connection
How these two moments in the story relate
From
Doctor tries to outwit the locked cell
S18E23
·
The Keeper of Traken Part 3
To
Doctor plots escape amid Kassia's treachery
S18E23
·
The Keeper of Traken Part 3
Why These Connect
The narrative assertion
"The Doctor's failed attempt to open the cell door with a sonic screwdriver sets up the need for alternative means of escape, which Nyssa later provides, emphasizing the Doctor's reliance on his companions' ingenuity."
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.