It doesn't at all. She could have done that in a way that didn't involve all that garbage. She also could have done that at any time to any person undergoing homecoming. She could have used her brain sync super power to tell noah and friends. Not to mention the party has dispatched like a half dozen moebeus at this point. There's plenty of ways for her to die and avoid the flow or more practically she should help us until we win and then she can fade away. How many innocent kevesi and agnian and lost number soldiers died during that month we were imprisoned? She stole a month from the rest of the cast who only have like a year or two left anyway.
Had she done it to a random other person undergoing Homecoming, odds are N would have clued in and just stabbed that person the old-fashioned way. By swapping with her alternate self - who understands her feelings, beliefs, and intentions because she holds the same ones - putting together a convincing ruse becomes significantly more feasible. I could also very easily believe that M was only able to perform a complete swap because Mio is her alternate self and there were so many pre-existing similarities to help line everything up and avoid conspicuous resistance.
Homecomings are also pretty rare, and I don't think it's normal for M to hang out at them (I could be wrong, but I don't think N was present at the Kevesi one we saw), so attending a normal one would arouse suspicion. Finding an opportunity to do that at the same time as there's a set of Ouroboros candidates running around that stands a genuine chance of winning (if there weren't, N would massacre most of the world in his ensuing rage) seems astronomically unlikely, to the point that her seizing this one good opportunity makes perfect sense.
YoukaiSlayer posted...
N's beyond redeaming. How can you redeem eons of genocide? He doesn't deserve to have his time move again.
Noah is N's redemption, just as Mio is M's. They represent their past selves' regret over making the wrong choice (to become Moebius, in N's case, and M's failure to keep N from falling to such despair). The only reason Noah didn't fall to despair like N did is because M made sure Mio was around to keep him on the right path and remind him that he was fighting for something so much bigger than his personal feelings (through the flashback sequence). He passed that test, and in doing so redeemed N by re-committing to the goal of saving the world instead of being led astray by despair (seen when N merges with Noah after the fight with him in Origin, which is loosely analogous to Egil in the Mechonis Core fight in that it amounts to "we want the same thing, let go of your hate so we can actually achieve it").
Basically, Noah had to watch Mio die and overcome that, because failing to do so is what gave birth to N. If Noah had failed that test, he'd just have become another N (or merged with the existing one, I'm not sure). If Noah had been given an easy out and Mio's life had been extended without him ever truly having to face was her death would mean for him, he likely would have faltered when faced with the reality that Ouroboros had to separate the worlds and say goodbye to each other.
YoukaiSlayer posted...
There's then a bit of technical mess up. When the blade calling was sealed, it wasn't stopped completely, it just disappeared before being fully formed. Seems very plausible to at least try to attack in that moment when it's partially formed to destroy the iron bars. Also, they explain earlier but the circles on lanz armor is because it's a powerframe and the circles are still lit up so he and probably sena should have been able to bash down that door without calling blades. Especially if it was just iron. The gaps are also easily large enough for the smaller party members to slip through, especially the nopon.
The whole "power frame" thing is kind of a silly mcguffin to begin with that only exists to address the "plot hole" of how much more powerful a nation of blade/flesh eaters would be than normal people (never mind that those normal people were blocking hits from 400-ton robots on a regular basis), but I'm pretty comfortable accepting that whatever was done to seal their blades and Ouroboros powers also weakened power frames and blade genetics by enough to give the observed effect. Even if it hadn't and they were able to escape somehow, they'd near-instantly be arrested again, so call it a matter of convenience to avoid animating that process.
YoukaiSlayer posted...
Why did the lost numbers not show up until right AFTER the eclipse? The had like a week of prep time and showed up minutes too late for no reason and didn't even attempt to destroy the annihilator cannon.
If they'd destroyed the annihilator before the eclipse, it would have tipped N off to M's betrayal, since they should have no way of knowing about it. They should also have no way of knowing about the homecoming or even that the party is still alive, given that everyone that could have known about the outcome of the battle was captured afterwards, plus the whole event was so heavily guarded that attacking before the chaos of Noah's breakthrough would have been pretty suicidal.
YoukaiSlayer posted...
Finally, why didn't noah attempt to draw lucky seven? It's not a blade. Riku even tells him to draw it, Noah breaks free for a moment, and...doesn't even try. Wtf? I was so angry watching that. Every damn xenoblade has to ruin it's story in the latter half.
Presumably because he was too overcome by despair to try (especially in the context of "here's the flute that's given you such comfort and peace for your entire life, use it to destroy your new favourite thing), but it also ties into the nature of the Sword of Origin (which seems to be tied to Lucky Seven because Riku is just ordinary nopon): It's a weapon meant to destroy the world that Moebius created. Until he truly committed himself to doing that - regardless of what he would have to lose in the process - he wasn't able to use it. It's never outright stated, but N seems to have had access to a sword of similar power (which is why Z was so personally interested in him) that ended up being corrupted by his desire to protect the present. It stands to reason that the replacement that was built into subsequent Ouroboros stones was designed to prevent that corruption by only becoming available to those that were sufficiently determined.
I'm also not sure where you're getting that every Xenoblade ruins its story in the latter half. 2 basically doesn't even have a story until the last ~25% of the game, unless you were really attached to "we're going to steal your girlfriend because we're evil" "Oh no please don't steal my girlfriend." Virtually all of 2's story value is loaded into huge dumps of worldbuilding and exposing characters' motivations (particularly on the villains' side) and having the party reconcile that information with their beliefs, and almost all of that happens in or after chapter 7.
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