Doctor Who: 20 Things You Didn’t Know About The Waters Of Mars
7. Mia And Yuri Had A Daughter
Both Mia and Yuri were spared their original fates when the Doctor broke his own interference rules and rescued them from their exploding base.
The last shot of them on TV is Yuri running after Mia as the gravity of the situation gets too much for her, but that isn't where their story ended.
As revealed in the 2023 novelisation of the story (which includes far more references to the couple's on-base romance), it's revealed that Yuri and Mia stayed together after their rescue, and even had a child.
They used this as an opportunity to honour their fallen comrade, naming their first-born daughter Adelaide.