I was under the impression that the 1940 Dunkirk evacuation (5.26 to 6.4) was an unruly, somewhat chaotic thing. As any evacuation under duress would be. I never imagined that the defeated British troops, anxious and scared, would stand so still and quietly, and that all of that windblown sand would look so captivating. But Chris Nolan, director-writer of Dunkirk (Warner Bros., 7.21.17), has. No matter — the chilling sequence at the end (the 31-second to the 46-second mark) makes it all worth it.