Snip!
I hate being a geek some days because my mind whirls and analyzes things, especially with the evidence that we're given.
Like how Alice (admittedly in armor) soaks an antimaterial round to the face. A round like that can severely deform over an inch and a half of titanium. That's nasty. (Okay, we don't know what kind of round Sedna was firing while in combat mode, or... Yeah.) Or how Alice tanks that fall from the wind turbine. While both of these are kinetic damage, they're very different.
Now, I won't lynch Jeff if he says nanomachines in the end despite how that makes me twitch uncomfortably. It's his story, not mine, and he's entitled to use whatever explanations he wants to give, if he chooses to give any. The story is solid, and that's the most important thing, right?
Failing that, if I were to hazard a guess, I'd go ahead and suggest that their skin has either a technological or biological high shear non-Newtonian fluid that operates down to a near-molecular level along with some other mechanism to spread out impacts over a greater range. The armor behaves like cloth, but appears to offer more protection. I would randomly guess that it behaves on a similar principle as the skin, along with some sort of super-dense crystalline latticework going on at a molecular level that... Okay, you know what, let's skip this unless people want more and just fast forward.
I'm torn on if Alice is more biotech or.... normal tech? Non-biotech? I'll just call it tech for now. On one hand, it's implied that her hair grows by Sedna. That seems silly to have on non-biotech units. On the other hand, summoning armor like that, or deploying it somehow, would require a degree of tech that would be hard to reproduce with biotech. But Sedna illustrates that they're probably anatomically correct, which seems weird and mildly fetishy for tech, but more plausible for a biotech unit made off a human pattern. But on the other hand...
...What's this about "MST3K Mantra?" Just shut up and enjoy the ride? B-but my geek cred demands that I figure this out and show everybody that I'm smart! I... Fine, I'll go sit in the corner and write "nobody wants to read fifteen pages of technobabble but me, even if Jeff seems to put thought into his" a thousand times. Sorry. I promise not to do it in public again.