
That she would be more capable than many older than she is a given. How did such a thing happen? That my sister would have wanted to be there, I have no doubt.

Suddenly, I'm thinking of Prim, who was not yet fourteen, not yet old enough to be granted the title of soldier, but somehow working on the front lines. In the book, Katniss's internal monologue (obviously missing from the film) brings her to a different conclusion: Perhaps he said "I'm sure he wasn't gunning for your sister" just to put the opposite possibility into Katniss's mind without openly endorsing it. However, it must be borne in mind that Snow is both a hated enemy and a skilled politician. (this quote is from the book Mockingjay, but the whole rose garden conversation goes down very very similarly in the film Mockingjay: Part 2) "I'm sure he wasn't gunning for your sister, but these things happen." Well, it's that sort of thinking that you look for in a Head Gamemaker, isn't it?" Snow dabs the corners of his mouth. Did you know it aired live? You can see Plutarch's hand there. The idea that I was bombing our own helpless children instantly snapped whatever frail allegiance my people still felt to me. "However, I must concede it was a masterful move on Coin's part.
This is what Snow suggests when he tells Katniss it was Coin who had those bombs dropped: Perhaps by chance she happened to be on duty at the moment when the bombs were dropped on the Capitol children, and ran to help as part of her medical team. As a comment already mentioned, Prim was working as a medic for the rebels (this is established earlier in the film, while they're in the underground bunker together during the Capitol's bombardment of Thirteen).
