The Doctor uses the sentient entity known as "Passenger," which has an infinite internal capacity, to absorb the destructive energy of the Flux and save what remains of the universe. Villain Defeat:
The Sontarans trick the Daleks and Cybermen into an alliance, intending to sacrifice them to the final Flux wave while remaining safe behind a Lupari shield. [S13E6] Chapter Six: The Vanquishers
The Doctor decides not to open the fob watch containing her lost memories, choosing instead to hide it deep within the TARDIS. Character Fates & Critiques Doctor Who: Series 13, Episode 6 – Flux: Chapter Six The Doctor uses the sentient entity known as
He is ultimately outmaneuvered by Kate Stewart and Vinder, who exile him to a lonely asteroid. Character Fates & Critiques Doctor Who: Series 13,
The Doctor splits herself into three separate versions across space and time—one on the Sontaran ship, one in the TARDIS, and one in the Division's corridors—to coordinate the counter-attack.