Doctor Who: The Timey-Wimiest Episodes Not By Steven Moffat
8. Spyfall Parts 1 & 2 (2020)
Spyfall involves the Thirteenth Doctor foiling a plot of the Master’s to team up with an evil human entrepreneur and a race of would-be alien conquerors to turn humanity into a series of hard drives.
As the story progresses, the Doctor is transported back in time to the 1900s and meets the Master at various of points in history, as the villain attempts to sabotage humanity’s development of computer science.
In the course of things, the Doctor’s companions are nearly killed in a plane crash, but are saved via some clever preparation that the Doctor evidently did earlier. When they later ask the Doctor how she did this, she realizes that she didn’t, at least not yet. She quickly nips off, uses time travel to once again effect some adjustments to things, and then returns, having retroactively saved her companion’s lives through her actions.