Wouldn't this be a better solution...

If I wanted to capture the opponent. Then I would wear them down mentally and play the weakest link. If I'm a German soldier I think I would be feeling full of myself after having just marched into Poland and claiming it. War is just a board game. Either take the piece or break the peace. I'm sure the soldiers could improvise as long as negotiations were being discussed by world leaders. If I'm Nolan I can take A Serious Man approach to Dunkirk. Give it a little dark humor. A quarrel between two neighbors. I would write around that scenario. It doesn't have to be funny. But if the end result of the opening act is related to the first line of the movie...( no idea. I'm sure if you actually write or understand the art then you get what I'm saying)

We have what we seek, it is there all the time, and if we give it time, it will make itself known.