Following the major reveal of the character in the latest finale, Russell T Davies and Anita Dobson address the current status of the mystery of Doctor Who's Mrs. Flood. Dobson made her debut in "The Church on Ruby Road" as the seemingly ordinary neighbor to the Sunday family, though it would be revealed that she has hidden knowledge of the Time Lords that has left viewers guessing her true identity. After having brief appearances in season 14, Flood starred in a guest role across the two-part finale "The Legend of Ruby Sunday/Empire of Death", which provided more hints.
With Doctor Who season 14 bringing the mystery of Ruby Sunday (Millie Gibson) and the One Who Waits to a close, Davies and Dobson addressed the remaining mystery of Mrs. Flood going into season 15 with Doctor Who: Unleashed. While the showrunner confirmed that Flood was not part of Sutekh's scheme, Davies did tease that she would play a key role in season 15, while Dobson described Flood as ever-evolving. Check out Davies' and Dobson's response below:
Russell T Davies: Clearly there’s a mystery with Mrs. Flood, played by Anita Dobson- Dobs, as I call her. We’ve seen way back in "The Church on Ruby Road", where Ncuti first appeared and when Millie first appeared. She was the next door neighbour, but then suddenly ends that episode with a great line to camera, where she goes “Never seen a TARDIS before”. So clearly, that’s saying “Something’s going on here.” She’s popped up then, living next door. We’ve seen her, she’s cast a little line in “73 Yards” on what’s going on. She gets a bit closer to the action in episode 7, she starts to reveal herself in episode 7. In episode 8, she had…. She says “I had such plans”. So she’s not part of what Sutekh was up to. She’s kind of trapped in whatever Sutekh was up to, in as much as the whole world is and says “I had such plans”. I wonder what that means…. I can promise you reveals, I can promise you astonishing reveals and a lot of fun with her as well. She’s so much fun to work with, so good times with Mrs. Flood to come.
Anita Dodson: Mrs Flood is sort of changing. We don’t quite know what into, but she’s definitely changing, yeah. Or else she needs to see a therapist, big time.
There’s got to be something with her and companions. At this point she’s got the Pond-River-style name (thank god at this point she doesn’t seem to be part of another tedious River Song storyline), she wore Clara’s Face The Raven outfit and called the Doctor a “clever boy,” and she ended the episode in Romana’s fur coat. I’m fully down with her trolling the Doctor/us like this - I just hope she’s not the Master again. There is no character in Doctor Who I’m as sick of as the Master.
(My outside bet is maybe the Meddling Monk? But that’s probably wrong.)
unless literally everything is a red herring, which is always possible.
RTD does like his red herrings. If anything is obvious then it is likely misdirection. At the end she gave off serious winter-themed Missy vibes, so it's not likely to be that.