- Acting for Two: Martha, as herself and Not Herself.
- Completely Different Title: The French title is "ATMOS Part 2".
- Serendipity Writes the Plot: Donna was originally meant to use a shoe to knock out the Sontarans, but because Catherine Tate only wears trainers they didn't want it to be a trainer, or they thought a trainer would be too soft and just bounce off the back of the neck. She got to use a mallet instead.
- Throw It In!: While filming the gas mask scene, David Tennant forgot his line. He spontaneously came up with the line "Are you my mummy?", because the mask reminded him of "The Empty Child"/"The Doctor Dances".
- What Could Have Been: When the Doctor cuts off Staal's speech on the video screen in mid flow, a clip from Tommy Zoom is featured. The original plan to use a clip from Shaun the Sheep fell through.
Trivia / Doctor Who S30 E5 "The Poison Sky"