Actually, that was what usually occurred. They took the train to Canada, where they joined up. They were then transported by ship to England.
You’re being polite: the whole movie was pointless. Last night I was surfing and saw that the extended version (sans harsh language, meaning the Chef has about 1/3 his usual lines) was on AMC. I was subjected to the French family dinner, which has to rate as the most boring sequence of any film, involving war or not, in history. Why anyone would shoot that sequence, much less go to the bother of inserting it in a film that was already insane without it, is beyond me.
Apocalypse Now: the most egregious waste of an interesting high concept in movie history.