12. How Did The Doctor Recognize Stenza Technology?
It looks as though the Doctor has been swotting up on the Stenza in the TARDIS databanks. She's now able to recognize Stenza technology at a glance, and can name their homeworld. The Stenza can presumably count themselves lucky the Doctor hasn't paid a house call.
11. How Did Tim Shaw Recreate So Much Stenza Technology?
The Doctor Who season 11 finale revealed a fascinating new detail about the Stenza; they possess a hive mind. There are subtle hints that the Stenza have no natural ability to innovate at all, perhaps explaining why they'd forced the population of Desolation to create weapons for them in "The Ghost Monument." Notice that Tim Shaw hasn't developed the technology at all in the 3,407 years he's been on Ranskoor Av Kolos - the Sniper Bots are identical to the ones seen in "The Ghost Monument."
10. Do All Stenza Have Such A Long Life?
The Doctor may have brushed up on the basics of the Stenza, but she's more than a little surprised to find Tim Shaw is still alive. Even Tim Shaw makes a throwaway remark about the fact he's remarkably long-lived for his race, so he's probably been kept alive by the power of the Ux. Indeed, this may in itself explain why one of the Ux suspected he wasn't a god at all.
9. What Is A Neural Balancer?
The neural balancer seems to be a device that regulates the brainwaves, helping protect against psychic interference. It makes sense for the Doctor to have this kind of technology aboard the TARDIS; previous episodes of Doctor Who have shown that the TARDIS telepathic circuits can malfunction on occasion. The most notable example was the William Hartnell two-parter "The Edge of Destruction," which first introduced the idea of the telepathic circuits and saw the TARDIS crew turn against one another, driven to fits of paranoia. After a few such incidents, the Doctor would surely decide to stock up on something like the neural balancers.
8. Does The Doctor Follow Her Own Rules?
The Doctor has always objected to weapons - and yet, in the Doctor Who season 11 finale she tells her friends to pick up some guns and grenades. The Doctor admits that she does play a little fast and loose with her rules, but this is a particularly surprising example - there have been precious few previous episodes where any incarnation of the Doctor has been happy with a weapon being used. These have frequently been the darkest moments in the Doctor's life, such as "The Day of the Doctor" or "Dalek."
7. Who Did Invent Wellies?
The Doctor has always loved to chatter aimlessly, and this time she randomly suggests that she "half-invented" the wellington boot. In reality, the wellington was created in the 18th Century when the Duke of Wellington instructed his shoemaker, Hoby of St. James's Street, London, to adapt the traditional Hessian boot. A popular political figure and a celebrated war leader, the Duke of Wellington's new footwear became highly fashionable.