Ah yes, Dunkirk is definitely missing an IC throughline. Personally, I didn't sense anything in the story pushing me to fill in that spot. It felt like the movie wanted the audience to maybe have a sense of pride when (kind of spoiler if you haven't seen it I guess) the private British citizens boats show up. I think Jim mentioned this in his article as well-that may be the only reason I noticed it. But otherwise, I didn't feel compelled to fill in any gaps.