After the Fourth Doctor was instructed to interfere with the creation of the Daleks, Sarah Jane Smith urged him to complete his "mission" for the Time Lords. (TV: Genesis of the Daleks)
In enlisting the assistance of Trev Simpkins at the Time Hotel, the Fifteenth Doctor told him that the two of them were on a top-secret dangerous mission, and indicated a man of interest, asking what mission this man was on with a briefcase chained to his wrist. Later, when Trev realised he was about to die after having had the briefcase, which held the star seed, transferred to himself, he lamented "But I was on a mission." Following this, his consciousness was transferred to the star seed and he was able to re-establish communication with the Doctor. He told him that the mission was proceeding broadly as planned, notwithstanding the fact that he was dead. Finally, after Joy Almondo took the star seed into herself, his holographic form gave the Doctor a double thumbs-up, telling him that the mission was complete. (TV: Joy to the World [+]Steven Moffat, Doctor Who Christmas Special 2024 (BBC One and Disney+, 2024).)