WARNING! THERE MAY BE UNMARKED SPOILERS!
- Accidental Aesop: In light of "The Curse of Peladon" being a pro-EU tract, the timeline here established turns this episode into a Brexit tract.
- Captain Obvious Aesop:
- The anvilicious "slavery's bad, mmmmkay?" aesop seems to have been a deliberate attempt at amends for the Fridge Horror of the Doctor basically saying "okie dokie" when he discovered the Ood slaves in "The Impossible Planet"/"The Satan Pit" and left them to die at the end of the episode. This is the main reason they made "Planet of The Ood", to address that fact. It's even lampshaded when Donna points out how uncharacteristic it is for the Doctor to not help the Ood. The Doctor points out he was battling Satan at the time and thus a little busy. Then he admits that he owes them one.
- One only slightly less obvious (but in some quarters probably still necessary) might be: "Even if a people doesn't look like you, and seems more primitive than you, that gives you no right to exploit them."
- There's a slightly more subtle Aesop at work as well. At one point when Donna's railing against the institutionalised slavery represented by the Ood, the Doctor points out that most of the clothes she's wearing at that very moment were manufactured in sweatshops by people living only a few steps above slavery. It suggests that although people in the west intellectually know slavery is bad and wouldn't tolerate it when they're directly exposed to it, if it's out of sight and they benefit from it they're likely to not give it much thought. The people overseeing the Ood Operations plant even say the same is applicable for the Ood.
- Harsher in Hindsight: It's sad for Donna to hear the song of the captured Ood, but it's even sadder for the viewers who have seen the end of the season. Donna can't handle something humans are not supposed to experience, and the Doctor blocks it for her.
- Hilarious in Hindsight: The wristwatch communicators that some of the characters are shown using don't seem too far fetched now that Apple and Google have introduced smartwatches capable of making phone calls independent of a smartphone.