Doctor Who: Every NuWho Companion Ranked From Worst To Best
13. Adelaide Brooke
The fate of little Adelaide may have differed in location and slight circumstance but nevertheless, her death affects the history of the Human Race and the fate of one Time Lord, no longer victorious.
The Waters of Mars has only improved with time, while remaining one of the darkest stories in The Tenth Doctor's tenure. Faced with the knowledge that his own time is running out, The Doctor starts to become reckless. The destruction of Bowie Base One on the surface of Mars is, like Pompeii, a fixed point in time and therefore cannot be altered. Adelaide Brooke understands this, while The Doctor tries to rise above the rules set in place.
In a scene that remains shocking to this day, Adelaide, when brought back to Earth by The Doctor, confronts him over his changing of history, daring him to answer who he thinks he is and what right he has to mess with established events. When she sees she can't change his mind with words, she slowly returns to her home whilst removing her sidearm. In the next moment, The Doctor understands with crystal clarity the depths to which he has sank.