When Varada Sethu was cast in the 2024 Doctor Who episode “Boom” as hardened soldier Mundy Flynn, series showrunner Russell T Davies felt a surprising emotion: regret. The showrunner, who had recently returned to the show to reboot it for a new era on Disney+, was in the midst of searching for a new Doctor Who companion following the departure of Millie Gibson’s Ruby Sunday at the end of Season 1. And as he sat in the edit bay for “Boom,” written by fellow former showrunner Steven Moffat, he realized that Doctor Who had already cast the perfect actor for the role — as another character.
“In looking for this new companion, I kept watching ‘Boom,’” Russell T Davies tells Inverse. “Because bear in mind I sit at this desk and I watch 50 edits of ‘Boom.’ I know every single breath, every single semicolon, and every single pixel of the episode. And I used to sit there, time and time again thinking, ‘God, she's so brilliant. What a shame she's gone.’”
