In my headcannon, the MLP meet Nyssa and Tegan. And Tegan is force to face her sins; her prejurdicing Kamelion which drove him mad on ‘Demons in the Mist’, her blaming the Tremas Master for Borusa’s crimes, her choosing to force the 5th Doctor to slay Homo reptillia, her abandoning the Doctor after the Daleks, her beign a jerk to the 13th Doctor, and her bringing the Cybermen into UNIT. All of which be revela to’d help start the Time War and the Flux. And Furies torment her. And she sturggles, fearing Nyssa might reject her if she foudn out. But Nyssa already knew coz she overheard; acting oblivious and allwoign Tegan to tell out of sensitivity. And evne though she’d wronged, Rainbow and Flurtershy as well as Fizzy and the CMC chose to help.

Out of the two ladies, I prefer Nyssa. Nyssa’s braver and nicer than Tegan. Even when sick because of a Sontaran germ weapon, she was more concern for her pals. ANd Tegan abandon her Doctor as a coward, while Nyssa’s motive was self-sacrifice for the greater good.