Doctor Who: 12 Cool Details Revealed In Steven Moffat's Blink Commentary
4. Sally's Conversation With The Doctor Was The Hardest Thing To Write
The most crucial scene in the episode - the moment where everything finally clicks into place - is the timey-wimey "conversation" between Sally and the Doctor.
Here, we get to see both sides of this conversation in full (after only seeing bits of the Doctor's dialogue peppered throughout the episode), we learn what the Doctor needs Sally to do, and we also learn more details about the Angels themselves, with the Doctor's chilling line "blink and you're dead" sending shivers down the spines of Who fans everywhere - as well as scaring the pants off Sally and Larry.
On the commentary track, Moffat stated that this whole scene was a "nightmare" to write, and that it took him "several goes" to get it to a satisfactory spot.
With the rest of the episode proving so effective up until this point, he was worried - understandably - that the climax would be a disappointment. Hey Steven: it wasn't.