OK to start off, let me explain how I'll give critique here. Since this was written in such a short time, it doesn't seem fair to critique it on grounds of polish, grammar, etc. anything that would have been taken care of on future drafts. Instead, I'll report what I think you were going for and then my impressions, and you can hopefully use the "gap" between the two (if any) to inform future work. I'll also try to mention some techniques/tricks that I've personally found helpful that might also be applicable in bridging that gap. You are free to ignore these as you like.
I think you were primarily going for a tragic or melancholic feeling here. You want us to feel for Octavio and his wife, you want us to feel the depth of his heartbreak and inner conflict over their argument. You also want us to understand the positions of each side, why Octavio doesn't want to return, why his wife does; their mutually complicated feelings toward their homeland, the meaning of freedom and struggle, and their equally complicated relationship.
However, the impression I got was of a story that was constructed too mechanically. Everything is clear, but everything is so "set up" (the dialogue was particularly guilty of this) that it strains belief. To put it another way, the desire to have us understand their respective positions overrode the evocation of the emotions you were going for. In my view, emotions should always take primacy over understanding in fiction. That's not to say that you should write something incomprehensible but that comprehension should be in service of the emotional effect. So in this story, I have a pretty good idea of why each character has taken the position they have, you've made it abundantly clear. At the same time, I don't really care one way or another, because these characters don't really feel like flesh and blood. You weren't able to convince me these are real people, because, based on the "model of real people" in my head, their behavior doesn't follow.
That discrepancy can arise from two things: either your model is just drastically different than mine or you didn't actually tap into your model while you were writing this, instead (possibly due to the rush of the time limit) you were thinking about the logical requirements of the plot. I suspect it's latter, because I don't think my model is particularly special in that way or yours somehow deficient.
Let's think about these two characters for a second. They're old. They've been married for decades. I can't imagine they would communicate as directly as you've made them do in the story. Two people who have been together for so long would have an enormous amount of subtext in their every interaction. There would hardly be anything hidden between them. So the whole bit about the children, her being blindsided by his refusal, even his mild surprise at her wanting to go back just seems strange. I can imagine each of them to have rehearsed this conversation in their heads many times, to know what the other person is going to say and have a counter ready for it, to know what the other is thinking before they say a word. I can't imagine two people who have been so long together making these grandiose speeches to each other or replying so directly and unequivocally.
There are also a few moments which felt to me callous, i.e the author lacking compassion for his characters through omission. E.g imagine how guilty Octavio must feel for denying his wife children, how painful that is for him, yet when she brings it up, he just glosses over it completely. No mention of it whatsoever. Even if he doesn't address it in dialogue (and maybe he shouldn't) but there should have been a moment of internalization there to let us, the audience, feel his pain, and if he didn't feel anything, we should know that explicitly too--that will also evoke a reaction in the reader, and create dramatic irony--but omission has the effect of robbing the character of his humanity. There are a few moments like this. To be fair, you handle Octavio's wife better than Octavio himself (which indicates to me that maybe she should be the pov character here).
Now, regarding motivations. I can understand them, as I said before, but I don't feel them. This is partly because you inform us of circumstances, but not of meaning. What does freedom-fighting and the struggle actually mean to Octavio? In other words, why does he care so much? I get why his wife cares, she had to give up having children, the sense of a home, her family (but even this could have been made more concrete, as it is it feels like she's motivated by things in the abstract. If you really want us to feel her homesickness tell us about a particular niece, a particular spot, a memory etc.--as you do at the very end.) but with Octavio it's as if you expect the struggle/freedom, in the abstract, will automatically evoke emotion. In my experience, almost nothing in the abstract evokes emotion. I think this is the main source of the "gap" and fixing this will go a long ways toward infusing the work with the emotion I felt was lacking.
Some techniques that might be useful:
- If you can put the words "As you know" in front of a line of dialogue (i.e if it is something that wouuld be obvious to the characters, if not necessarily the reader), cut it. Then, if its necessary, put the line in as internalization or thought.
- Whereever you have an abstraction, ask yourself what it means concretely to the character--almost always it will have some association with a memory or experience, which you should then give a brief flashback of. That's essentially what character is, a string of memories and experiences which the character is interpreting through his present situation/state of mind.
- Related to #1, you can use internalization and thought to manage pacing as well as exposition. That's the place where you can "tell, not show" without annoying the reader. It's where you should build up the meaning of what you're trying to show--otherwise, tears and outbursts just seem melodramatic, because melodrama by definition is unjustified (according to that mental model) emotion or drama.