Punctuation is cohesive

It has meaning. Here's an example:

A couple has to make a decision: leave Iran to better the life of their child, or to stay and take care of a parent suffering from Alzheimer's, which could end their marriage.

Okay, based on that description, which is word-for-word and punctuation-mark-for-punctuation-mark off the On Demand menu, what threatens their marriage? Staying home, right? But it's the decision that does - she wants to leave, he feels obligated to stay - or rather, it's the existence of the decision, because she's not staying, so if he chooses to, she's leaving him. But the way that's punctuated, that's not what it says.

ps - the movie is A Separation, which is brilliant.