Continuing the "Bad Wolf" theme, the American newsreader announcing the UN's decision is named "Mal Loup", French for "Bad Wolf". The name does not appear in the televised clip, but is present on the version on Mickey's website.
The use of vinegar on calcium "just like Hannibal" references the story of how Hannibal's engineers, while crossing the Alps, heated boulders that blocked their way with wood fires, then poured vinegar over them. The rocks, weakened by the heat, were broken up by the vinegar into smaller pieces, which were then easily moved to clear a path.
The "next time..." preview at the end of the episode was criticized for revealing the following week's "surprise": the return of a Dalek, one of the Doctor's oldest and most evil enemies, in Dalek (2005). Later previews would also contain spoilers, prompting many fans to adopt the habit of immediately stopping watching when the preview starts on a new episode.
Unusually, the repetition of the last episode's cliffhanger before the credit/sequence contains the cliffhanger's resolution: the Doctor removes the ID badge from his clothing and applies it to a Slitheen.
When a Slitheen visits Mickey's flat, the word "Salford" can be seen graffitied on the wall near the elevator. Christopher Eccleston's hometown is Salford.