Doctor Who: 15 Greatest NuWho Deaths So Far
5. The Dalek (Dalek)
Given their portrayal as the ruthless unemotional archenemies of the Doctor, hardly anyone would have expected a Dalek to be the heart at the centre of an episode. However, that is the case in Rob Shearman's Series 1 episode Dalek, in which fans watch the titular genocidal pepperpot blast its way through a private army of security before realising it has been contaminated by human emotion and blowing itself up.
The build up that makes this demise affecting for viewers is gradual. The Dalek finds itself unable to kill Rose, whose emotions it inadvertantly gained when it tried to use her time-travelled DNA to reinvigorate itself. Then it gradually realises it wants more from life than just killing, shooting a hole in the roof just so it can see the sun (and confusing the Doctor who is trying to threaten it). This is when viewers discover it's dying and it asks Rose to order it to die so it can end its suffering.
On top of being an emotional climax to the episode, Whovians were given an important insight into the Dalek mindset. Emotion isn't just loathed, it's seen as a sickness by them. It also acted as a mini-resolution to the Time War (for then, at least) and the Doctor's bittersweet triumph was played excellently by Christopher Eccleston.