Causal
strong strength
Narrative Connection
How these two moments in the story relate
From
President risks cosmic law to summon past Doctors
S10E1
·
The Three Doctors Part 1
To
Second Doctor arrives in TARDIS entrance
S10E1
·
The Three Doctors Part 1
Why These Connect
The narrative assertion
"The Time Lords' activation of the Doctor's time stream leads to the Second Doctor's sudden appearance in the TARDIS, introducing a critical new dynamic to the story."
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.