Did Missy Really Not Regenerate in the 'Doctor Who' Finale?

There were a lot of shocking twists in the Doctor Who season 10 finale, but the strangest was easily the time-paradox double-murder-double suicide perpetrated by Missy/the Master. What exactly happened here? Did Missy plan the whole thing? Or did the Master some how actually prevent his future-self from regenerating into another person after Missy dies?

Spoilers ahead for Doctor Who 10th season finale, “The Doctor Falls”

While fans have known for awhile that Michelle Gomez was departing Doctor Who, she was perviously evasive about whether Missy would regenerate onscreen or not. Back on May 19, Gomez told Inverse that “no one” was “prepared” for Missy regenerating. And now, it looks like what she said was true, from a certain point of view. Audiences didn’t see Missy regenerate. But if the Master is to believed, she can’t.

Here’s what’s confusing: it seems like Missy does in fact remember everything that happens in both “World Enough and Time” and “The Doctor Falls.” Though she feigns recognizing the Master in “World Enough and Time,” her eventual betrayal of her former self seems to prove she remembers everything that has happened to him. And that’s because it all happened to her when she was still the Master.

So, if that’s true, why wouldn’t she remember the Master giving her a lethal blast from his laser screwdriver? And wouldn’t she make preparations for something that would — supposedly — prevent her from future regenerations?

The easy answer is: she totally did. We don’t actually see Missy “die” in the episode, nor do we see the Master regenerate into her officially. So, what’s the deal? Did the Master somehow change the timeline and kill his future self? Early in “The Doctor Falls,” Missy tells the Master that she’s “a bit hazy on the whole regeneration thing, I’m afraid.” Now, it’s possible that this part is true. Missy remembers all the things that have happened to this version of herself, but she hasn’t always remembered it clearly. Perhaps the memories “caught up” to her as the events unfolded.

In “The Day of the Doctor,” there’s a precedent for this kind of instant memory-making. When three versions of the Doctor (also a Time Lord like Missy/the Master) are all hanging out, they’re able to retroactively create a memory of the calculations that could help save Gallifrey. And this same thing could have happened with Missy. As she starts to decide to betray her former self, she suddenly remembers doing it. But before, when the time streams were “out of synch,” she couldn’t remember any of it.

If we’re being critical, this whole “time streams out of synch” thing is a massive plot contrivance that isn’t super consistent. Maybe the easier explanation as to why Missy is “hazy” on all of this is simple: like the Doctor, she actually does forget stuff. The very first 12th Doctor episode, “Deep Breath,” established that the heroic Time Lord had in fact forgotten about the clockwork robots from “Girl in the Fireplace.” If the Doctor can forget stuff like that, then maybe Missy can forget details about her own regeneration…or lack thereof.

Though the Master is unlikely to return any time soon, the next Doctor Who episode is the Christmas Special, airing on BBC and BBC America on December 25.