Warning: Spoilers ahead for Doctor Who season 14, episode 4, “73 Yards.”

Doctor Who season 14, episode 4, “73 Yards,” is incredibly compelling for a variety of reasons, one of which is the fact that it categorically disproves a popular theory about the enigmatic Mrs. Flood. Played by Anita Dobson, Mrs. Flood first appears in the 2023 Doctor Who Christmas special, “The Church on Ruby Road.” Her knowledge of the TARDIS and overall demeanor has resulted in speculation regarding whether Dobson’s character is a familiar face in disguise. While Doctor Who hasn’t yet explained the mystery of Mrs. Flood, “73 Yards” does rule out one possibility.

Dobson returns to the Doctor Who season 14 cast as Mrs. Flood, but it’s not her presence in the episode that disproves one of the theories about her true identity. Instead, it’s a casting move for another character that negates one possible reveal pertaining to Anita Dobson’s character. It’s unclear if the secret of Mrs. Flood will be shared in the current season, as Russell T Davies may be waiting for Doctor Who season 15 for the big reveal. However, the showrunner does thankfully shed some light on the subject in “73 Yards.”

Doctor Who Season 14, Episode 4 Proves Mrs. Flood Isn’t An Older Ruby Sunday

Old Ruby is played by Amanda Walked in “73 Yards”

A common theory among the Doctor Who fan base is that Mrs. Flood was simply an older version of Millie Gibson’s character. However, “73 Yards” definitely proves that this isn’t the case. Toward the end of Doctor Who seadon 14, episode 4, a much older version of Ruby Sunday is shown visiting the Doctor’s abandoned TARDIS. During this sequence, and the scene where she passes away, Ruby Sunday is portrayed by Amanda Walker.

At this time, Ruby is roughly 80 years old. As such, it would have made sense for Anita Dobson to play the character – if Mrs. Flood were Ruby all along. The fact that Walker was cast to play Old Ruby logically rules out the possibility of Mrs. Flood also being Ruby Sunday. So, while Russell T Davies still hasn’t given a solid answer to the question of who Mrs. Flood really is, he has at least removed Ruby from contention.

These Mrs. Flood Theories Just Became Way More Likely

Doctor Who still has plenty of room for speculation about Mrs. Flood’s identity

Now that it’s established that Mrs. Flood isn’t Ruby Sunday, it brings other theories to the front of the pack. For instance, the theory that Mrs. Flood is a new regeneration of River Song remains a possibility, especially because she doesn’t seem fazed by the presence of the strange woman at the end of the road. Dobson’s character may also be connected to Doctor Who‘s Pantheon, or perhaps even be the Doctor’s granddaughter – Susan Foreman. Unfortunately, clues are currently scarce, and Doctor Who will need to progress further if the mystery is to be solved.