- Inferred Holocaust: The end of last episode had the Sontarans activating 400 million cars to spew out the suffocating ATMOS gas. This episode establishes that every country in Europe has thousands of people walking across country to escape while, in Dunkirk fashion, boats take refugees out into the Atlantic from America's eastern seaboard as the first deaths are reported in Tokyo. Remembering that number, 400 million cars, one has to wonder how many people were caught in the same predicament as Wilf, locked inside their car and suffocating, only not lucky enough to be broken out.
- Like You Would Really Do It: At the climax, it turns out the only way to defeat the Sontarans is for one person to teleport themselves to the Sontaran ship and blow it up at the cost of a Heroic Sacrifice. There are only four people nearby who could do it: the Doctor, his current companion, his former companion, and the guest star who sold out all humanity to the Sontarans but is now seeking to redeem himself. (The Doctor thinks it'll be himself.)
YMMV / Doctor Who S30 E5 "The Poison Sky"