To answer everyone, I think there's supporting evidence that we're following two different Asukas on that particular sequence.
The first one we see smirking right after finishing her simulation. The other, who shows up right after, doesn't appear that happy though (despite having achieved identical results to her other self). This is the Asuka we see mirroring Ritsuko from EOE. She is miserable and can't escape (we literally see this happening). She was born in a frozen wasteland. She doesn't have free will and she knows it. Those trees she stares at? Those are like her and the others. They're all the same and they're all dying. So why was she so grim after the simulation while her other self was relieved? Because she knows she's succeeding. And that means everybody else is dying. In the end, only two Asukas remained. Which of the two survived? Which of the two is our Asuka? We don't really know and I think that's the ambiguity at play here. Remember, Asuka knows about all the other clones. Again, I do think that when she said "I'm not like them! I'm special" and "you can only count on yourself, Asuka" she was talking about the other Shikinamis, not Shinji and Rei. Still, this Asuka behaves very differently from the one we see in those flashbacks, doesn't she? Perhaps that first one we see in the simulation is the one who survived. Who knows?
(kudos to my friend Reichu for helping me wrap my head around this scene way back in 2021)
AsukaShikinami10 wrote:If that was the case, she would have contaminanted Unit-02 from the very beggining
Whatever was inside her was awakened by Unit 03 and this is symbolized by her growing wings (like many other Evangelions throughout the entire series). Asuka has many connections to these wings in NTE. They are also present in the code 999 sequence and are featured in her simulation plugsuit (the one we see in her flashbacks during the instrumentality). Besides, we can clearly see that Unit 03's signature blue goo comes from within her. Let's also not forget that girl's face that we see inside the entry plug in that scene, indicating that something was already inside and it looked like Asuka.
Just sit here and waste your precious time. When you want to do something, don't do it right away. Don't do it when you can. Read my posts instead. It's the only way to live a life without regrets.