. The whole Shinji's dialogue with Rei which follows afterwards loses its meaning if you assume the coffee pot scene happened exclusively in Shinji's mind and real Asuka wasn't involved.
Emboldened for you. This very line means Shinji experienced the taste of true Instrumentality, instead of attempting to play some model simulation of it, as you seem to claim (though I must admit I'm not quite sure have I properly understood you, or are you chasing some other thought).
Hi ErgoProxy o/ thank you for your insight
So based on my recent posts I didn't actually come to the conclusion that it was just a model simulation being played out in his head, I did my best to state that from the evidence and information I've collected from the posters here and other's theories, both situations were definitely possible. < Sachi's analysis supports the idea that Shinji's way of coping with his personal anxiety and fear of rejection stemmed the reactions he felt he would get from the girls during his internal conflict, meaning in his opinion based on Shinji's character, it was likely going on in just his mind. But the fact that he was shown Misato / Kaji's past shows that their thoughts could have been unified during certain points inside Shinji's mind.
The other posters used similar evidence to support the idea that they weren't just model simulations / projections in Shinji's mind but nothing gives us a for sure answer for either claim being the right one. So I came to accept that both are indeed possible and have good evidence to support each of them being true.
But what I strongly want to believe is that it was actually Asuka's soul experiencing the hell train scene / coffee pot argument with Shinji, as it gave great clarification on how they felt about each other.
I'm already convinced that Rei conveyed her feelings as she had a direct hand in what Shinji was going through. But if what Misato / Asuka were saying was Shinji's thoughts or actually them is still up to debate, except of course diving into Misato / Kaji's past but that alone doesn't say for sure that it was Asuka / Misato / Rei speaking to him during his internal conflict. It could've just been that they had access to each other's memories and thoughts but weren't directly communicating with each other.