Doctor Who: 11 Most Memorable Companion Exits Of The Last Decade

8. Adelaide Brooke (The Waters Of Mars)

In 2009, to coincide with the show's behind the scenes cast and crew overhaul, the Doctor's adventures adopted a new temporary format which resulted in viewers being treated to a handful of 'specials' instead of its then usual complete run of 13 episodes. There might've been less of the Time Lord to go round but he still managed to make an impact with the effects of the first winter special, The Waters of Mars, proving to be particularly long lasting within the Doctor Who mythology. The Tenth Doctor was accompanied by 'companion of the week' Adelaide Brooke - portrayed by stage and screen veteran Lindsay Duncan - in the episode and while her encounter with the Time Lord was brief, it was far from uneventful. As commander of Bowie Base One on Mars, it was quickly established that Adelaide was one you would probably be best to not get on the wrong side of. The Doctor himself underestimated her significance, though, until events on the red planet took a dramatic turn for the worse. As it turns out, the Doctor had arrived on the day that Adelaide Brooke was supposed to die which put him in a particularly tricky situation when it transpired that her heroic demise would go down in Earth history for inspiring future generations to continue their exploration of the universe. As such, her death was a fixed point in time but luckily - or perhaps unluckily - for her, this conundrum coincided with the Doctor's new found assumption, as the last surviving Time Lord, that time was his playground and that he could change the course of history as and when he pleased. Not pompous at all then. Things escalated rather quickly after that. He saved Adelaide but she eventually committed suicide in order to put time back on its right course. It's a memorable moment as one of the show's more serious explorations of just how dangerous an encounter with a time traveller can be. As Adelaide discovered, the consequences of changing time can be fatal.