Quite a good episode.
Since the top post as "SPOILER" flagged, the rest of this post contains big spoilers. No worries, if you have a phone with a newsfeed you probably saw all of the following and gobs more long before seeing the actual episode.


I thought the Doctor would have been the fugitive. But I didn't guess the Chameleon Arch and a different incarnation.
The Judoon were used reasonably well.
Maybe the new Doctor will retcon 2017 to where Jo is the real Doctor instead of Jodie. Jo did so much better as Ruth and the Doctor (Doctor Ruth*??) in one scene-- She is fricking awesome, and it's a nice touch by Chibnall** and who might be a ghost writer (2nd time this season people have postulated
that) that she doesn't recognize the sonic screwdriver magic wand crutch and calls the TARDIS "ship". If she is pre-Hartnell, there's a new set of incarnations granted to her to become Hartnell for a new regeneration run, but the TARDIS didn't get stuck in its police box form until
after "An Unearthly Child" pt 1.))
Okay, the teleporter device is a bit new but I'll roll with it. The scene that follows is utterly fab. Especially outing the magic wand garbage, of which the Doctor has a field day ridiculing and with a more natural sense of humor than the lame attempts to borrow Tennant and Smith jokes.
The Doctor's TARDIS is in the vibe of the real Doctor Who era (1963-89) but with modernizations that simply look cool.
And Dr Jo tells Dr Jodie not to talk, and has such screen presence.... actually, both of them have some great screen chemistry together. But Jo won me over in under one minute where Jodie, due to hideous scripts, needed a full year.
But why does nobody stop the Doctor Jodie when she reaches into her coat to get what could have been a weapon? (Great speech about Gallifrey being destroyed twice BTW...)
Of, Jodie Doctor forgot that Davison Doctor, Tom Baker Doctor, Colin Baker Doctor, and lots of other incarnations of Doctor used guns. Oops. Unless she's been the fake all along... so, yeah, Chibnall probably did write that bit.
A shame the companions were all somewhat sidelined but it was worth it.
* sorry for a low-hanging gag, but given Captain Jack (and an breaking introduction that narrowly avoids breaking the fourth wall) is there for audience scooping fodder (in case people didn't care for the other Doctor). Barrowman's charisma makes up for some somewhat generic dialogue anyone could have done but they really had to redo the assumption (and token one-sided tonguewrestle) that the Doctor is seen as male. It worked the first time but Jack of all people is far less likely to know, so I don't buy it. Ryan's right, he's cheesy but he is largely fun too. I still prefer and relate to Ryan more as a character though. And did they bring back Murray Gold for Jack's return and kissyfest moment? At least the Doctor wasn't there, the mistaken identity moment could have been far worse,
The Doctor explained regeneration in TWWFTE yet Yaz asks how Ruth could be the same person. But there's a nice setup in all this as to who is manipulating the Doctor (the Master, in some form somehow.)
And, yeah, the same episode foreshadows at least one companion leaving at the end of the year. A shame, the trio has grown on me considerably. Would love to see them interact with Jo far more.
Great setup/lead-in for next week's episode too. I just hope the arc and its denouement doesn't shatter.
** I believe him when he said he interviewed a bunch of people and she had the best talent for what he wanted in this incarnation