We've known Jenna Coleman's departure from Doctor Who was coming, the news broke several weeks ago, but most people (and myself included) would have thought that her end would come in the closing story of the series, not with two episodes left to go.
The shock of Coleman's sudden departure this episode is what made her death stand out for me. Right up until the point when the smoke came out of her lifeless mouth I was expecting her to somehow survive, to use the episode as a curve ball to make the audience believe she was going to die before letting her live for a few more episodes. Alas, that was not so and Clara Oswald met her end for no reason, dieing simply from her own stupidity.
Her intentions may have been pure, to remove the threat of death from Rigsy, but she was in full possession of the facts, as she came to realise at the end of the episode, that she was doomed the second she took the mark.
The thing is, was that really a surprise? If you watch Clara over the course of this series she's a very different person from who she was last year. She's taking more risks, she acting recklessly and literally laughing in the face of danger (like when nearly falling out of the Tardis in this episode). She has been putting herself in more and more danger each episode.
Whilst some of that can be chalked up to her cockiness, and she has been extremely cocky in the role of companion since the first episode in which we met Rigsy where she was left to play the part of The Doctor whilst he was stuck inside a miniturised Tardis, it's not just down to her thinking highly of herself and her skills. No, this is all down to the death of Danny Pink.
Danny died in last series finale, and Clara hasn't been the same since, a fact that she even acknowledges just before her death. She's been throwing herself into danger because she hasn't really cared about living as much as she was before. Whether it was conscious or not, she didn't care about her safety any more, even to the point where it had The Doctor worried.
The moments leading up to Clara's death are what really made this a good episode. Up to that point we were given a mystery story, the return of some previous characters in the form of Rigsy and Ashildr and a new piece of Doctor Who mythology in the form of hidden refugee settlements for some of The Doctors fallen foes.
It was as soon as the characters realised Clara was about to die, with no way to save her, that things really got interesting though. These are the kinds of moments where I love seeing Peter Capaldi in the role of The Doctor. He was able to portray despair, sadness, anger, frustration, hopelessness and simmering rage in such wonderfully subtle ways. You could see all those emotions swimming just under the surface whilst he tried to maintain a brave face for his friend. This scene is definitely up their with his speech at the end of the Zygon two parter as showcase moment that perfectly displays why he's one of the best Doctors we've had.
All in all I was very happy with the episode, it introduced some new ideas to the show, brought back some characters and monsters from the last few seasons and set up brilliantly for what looks to be one of the more unique season finales we've had, one with The Doctor alone and companionless (unless Missy comes back to help for the last episode).
It was also good as it was the first episode since the show returned that had the nerve to kill a companion. Whilst Donna's end was extremely sad (sadder than Clara's) she was still alive and ended up rich and married, and whilst Amy and Rory never saw The Doctor again they both lives into their old age, so those 'deaths' didn't count. This one does though.
Sometimes it's good to remind the audience that travelling with The Doctor isn't safe, at all. It's good to show that the good guys don't always win, and it helps to remind people that whilst Doctor Who is a family show characters still aren't safe, even companions.
A great start to the series finale and excellently acted by both Capaldi and Coleman.