*Spoilers*
I would like to know if anyone has a reasonable answer or theory to this question. When E1 or S1 go into the guest house, where would S2/E2 go? E1 and S1 figured out only one person can go in at a time, so what about the second couple? Did I miss something in the film or am I over thinking it?
Remember when Ethan got confined to the house? Maybe they get confined to another room in the house. Or they go to a different dimension in the same house (since the breakfast Sophie 2 was cooking disappeared with her).
shareYa, maybe both of them get confined to a room, and when E1 enters, only S2 can exit that room and vice versa.
sharePlus E2 and S2 knew that this happened; they specifically explained how E1 "cheated" the "system" that one time. This means they either could see it or just knew it for other reasons... personally, I like a sort of parallel world scenario but it matters not.
There are quite a few things that begs answers, remember also how E1 could not enter and even brake windows.... that is strange too. Of all the oddness, I think the best answer is really that it is just a kind of magic. Because none of this really matters to the theme of the story, I believe.
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** I am normally not a praying man, but if you are up there, please save me Superman **