Theory:Doctor Who television discontinuity and plot holes/The Zygon Invasion


 * The Doctor is the President of the World here, but nobody really cares or follows his commands.
 * This isn't an extinction-level event, plus I don't think the Doctor's presidency includes military authority. Or maybe he's been imposed in favour of someone who stays on Earth more often. President of the World Jack Harkness, anyone?
 * It is a potential global Invasion and UNIT as stated in this episode has command over the military so the President of the World should have as well.


 * During the opposite titles scene, how can The Doctor, a middle aged looking man, with a camera phone, openly sit in a children's play park and just watch the kids? Surly the parents/guardians would have taken children else where if there was just a man sat in a park.
 * Why exactly? We don't know about the local culture where that playground was. At least in my area that's actually quite common.
 * A strange question. Why wouldn't a middle-aged man openly sit in a playground? Also, almost everyone has a mobile phone, and almost all of them have cameras. Why would parents take their children elsewhere just because someone, middle-aged or not, is sitting there? Lastly, middle-aged people are often parents or grand-parents.
 * Although from some perspective this might look a bit creepy, who is to say the other people on the playground didn't suppose he was there with the kids as their grandfather?


 * Why does Kate mispronounce "Zed" as "Zee" when she mentions Z-67 in the episodes 'The Zygon Invasion" and "The Zygon Inversion"?
 * Some people just have a hard time telling the difference between the two pronunciations (even I tend to get mixed up with them).


 * Why did UNIT create a Zygon-killing gas in the first place? Zygons aren't like the Daleks or the Cybermen in that they aren't bulletproof, so why create a weapon that can kill a race that doesn't need special weapons to deal with them? Or was it specially tuned to only kill Zygons if UNIT weren't sure if they were facing against actual people or Zygons impersonating them?
 * The second one. I’m fairly sure the gas was tied to Zygon DNA.