Warning: MAJOR spoilers ahead for Doctor Who season 14, episode 7, “The Legend of Ruby Sunday.”

The Doctor Who season 14 finale looks as if it’s going to be an incredibly high-stakes affair, which will make it very weird if the Fourteenth Doctor and Donna Noble stay away from the story. The ending of the Doctor Who 60th-anniversary specials introduced a brand-new bi-generation twist to the franchise. As a result, David Tennant’s Fourteenth Doctor was able to retain his autonomy, while Ncuti Gatwa’s Fifteenth iteration entered the fray to take the reins. Although Fourteen essentially retired from his signature heroics, he still has traits that won’t vanish so quickly.

Catherine Tate’s Donna Noble also returned for the 60th-anniversary celebrations, with her character regaining all the memories that Tennant’s Tenth Doctor forced her to forget all the way back in the Doctor Who season 4 finale. As a result, both Tate and Tennant’s Doctor Who characters are back at the height of their powers and could conceivably reappear in the show at any time. While their absence hasn’t been an issue so far, it very well could be as the first season of Doctor Who‘s Disney era draws to a close.

The Fourteenth Doctor & Donna Can’t Ignore The Battle Against Sutekh

Fourteen’s retirement isn’t worth losing to Sutekh

Donna Noble now works for UNIT, and while her daughter Rose is seen to be hard at work for the organization in “The Legend of Ruby Sunday,” Donna is nowhere to be seen. As the Fourteenth Doctor has entered a new phase of life that centers more around the day-to-day, it’s slightly more understandable that he isn’t initially present. Then again, he has a fully functioning duplicate of the TARDIS – a fact that could be crucial given the reintroduction of Sutekh – it’s confusing why his blue box hasn’t alerted the retired Time Lord to the danger at hand.

Now, everything unfolds rather quickly in “The Legend of Ruby Sunday,” so the fact that Donna and Fourteen don’t come bursting onto the scene to help isn’t that distracting yet. However, Sutekh is an enormous threat to all life in the universe, so while Donna has a responsibility to show up and do her job for UNIT, the Fourteenth Doctor also no longer has the right to sit back and hope his successor can foil the leader of Doctor Who‘s Pantheon of Gods. Even considering doing so just isn’t within his nature.

The battle against Sutekh will be an all-hands-on-deck situation, and Donna and the Fourteenth Doctor are two of planet Earth’s biggest assets. Even if they somehow don’t immediately know what’s going on, Rose is at UNIT HQ and is fully aware of the danger everyone is in. So, there is at least one direct line to Donna and Fourteen – and there’s no reason why Rose wouldn’t call them to ask for their assistance.

Doctor Who’s 60th Anniversary Proved Fourteen & Fifteen Can Meet Without Causing A Paradox

Russell T Davies has painted himself into a narrative corner

Multi-Doctor stories aren’t an entirely common occurrence. While they’re an exciting event, the complex nature of the Doctor’s extensive timeline used to mean that any collaboration with his past or future selves could create a damaging paradox. A returning Doctor actor can also pull focus from the show’s current star, which can sometimes be a little unfair. This type of narrative is usually reserved for special events, such as anniversaries. Interestingly, Russell T Davies essentially removed the paradox roadblock by introducing the concept of bi-generation in “The Giggle.”

Although bi-generation is still poorly understood, the Fourteenth Doctor presumably won’t regenerate into Ncuti Gatwa’s version of the Time Lord. Even if he did, he wouldn’t be the same iteration of the character, as both Fourteen and Fifteen are now completely independent of one another. In other words, when the three Doctors met in the 50th anniversary special, a paradox was always on the horizon. Inversely, there’s no limit to the amount of interaction that Fourteen and Fifteen can share. Therefore, Davies has even less of a reason to omit David Tennant from the season 14 finale, “Empire of Death.”

David Tennant & Catherine Tate Are Unlikely To Return In Doctor Who Season 14’s Finale

Nucit Gatwa’s status as the franchise star needs to remain intact

Despite the logic of the Fourteenth Doctor’s return, as well as Donna Noble’s, the likelihood of them showing up in “Empire of Death” remains quite low. It’s shaping up to be Ncuti Gatwa’s biggest episode yet as the Doctor, so it would be arguably very unfair for him to share the spotlight – especially when so much of the focus of Doctor Who season 14 has already been on Millie Gibson’s Ruby Sunday.

Gatwa has quickly made a strong impression during his time as the Doctor, so while he could confidently share the screen with Tennant again without being forced into a secondary character role, Gatwa has earned the right to take on his first major villain without another Doctor helping him out. It’s just unfortunate that it’s canonically true that the Fourteenth Doctor still exists, and would legitimately show up given the dire circumstances. That being said, Tennant’s return isn’t completely beyond the realm of possibility, nor is Donna Noble’s.

One Sutekh Detail Shows How David Tennant’s Fourteenth Doctor Can Return

The second TARDIS in the CCTV footage needs explaining

When UNIT is analyzing the CCTV footage from the night of Ruby’s birth in “The Church on Ruby Road,” it turns out that a second TARDIS was present, “20 meters to the north” of the other. There have been several instances where two TARDIS’ have come into close contact, and it’s usually when a multi-Doctor story is in full swing. So, the fact that the Fourteenth Doctor also has a TARDIS becomes even more important as a result of the CCTV revelation.

The Sutekh reveal implies that the god of death took refuge inside the TARDIS long ago. In fact, Doctor Who season 14 is arguably a stealth sequel to a 1975 Tom Baker story called, “Pyramids of Mars.” So, if Sutekh has been within the TARDIS since Baker’s Doctor Who era, that could mean that he too was duplicated when the TARDIS was split into two in “The Giggle.” The other TARDIS in the CCTV footage in “The Legend of Ruby Sunday” could be Fourteen’s blue box, piloted to the night of Ruby’s birth by Sutekh without the Time Lord’s knowledge.

It’s also possible that the extra TARDIS is being piloted by the Fourteenth Doctor, as he tries to track down his counterpart. Either way, if it is the Fourteenth Doctor’s TARDIS in the CCTV footage, David Tennant’s version of the Time Lord won’t be far behind. Unfortunately, the whole truth of the situation will only be revealed when the Doctor Who season 14 finale, “Empire of Death,” hits Disney+.