Doctor Who: 8 Theories About Ryan And Graham's Departure In Revolution Of The Daleks

8. They Leave The Doctor Of Their Own Free Will

Arguably the least interesting way that Ryan and Graham could exit the show is that they might simply grow tired of travelling with the Doctor, deciding to return to their normal lives at the end of the episode.

It's actually been quite a long time since a companion left like this, with Martha Jones' farewell in 2007's Series 3 serving as the most recent example.

Every other main companion since then (Donna, Amy, Rory, Clara, Bill, and Nardole) has been separated from the Doctor against their will, and because of this, it might feel somewhat refreshing to see a companion departure like Martha's once again, rather than the deaths and memory wipes we've had since 2007.

Ryan and Graham both have friends on Earth and Graham also has his cancer fears, so there are plenty of reasons that showrunner/Revolution Of The Daleks writer Chris Chibnall could use to explain why they'd leave the Doctor voluntarily, and overall, it wouldn't be a total surprise if this is what happens.

That being said, each NuWho showrunner's first companion (Russell T Davies' Rose and Steven Moffat's Amy) has left under quite distressing circumstances, so perhaps Chibnall will stick to this pattern, whether he's intending to or not.