Revealing mistake: The ship set up for the capsize scene is supposedly mid channel and heading for England when it is bombed by the Heinkel, but it is at anchor.
Revealing mistake: In some of the shots where multiple British soldiers are together, most have their rifles (Short Magazine Lee Enfield, No. 1 Mk 3) slung or are holding them. Some of the rifles are dummy, toy rifles that look nothing like the Enfield and are just to stand in.
Answer: When George got injured, before he died, Peter did not understand what the soldier had been through. In fact he was honest with him when he asked if George was OK the first time. After he got to Dunkirk he saw what happens in war. What people went through. He understood why someone would be shell-shocked and empathized with the soldier more. After that he wanted to spare the soldiers feelings and not make him feel worse.