So one thing that both of Ranma 1/2's best arcs(The Ryo Kumon and Ryugenzawa arcs) does really, really well is that they manage to create strong, emotional stories by both deconstructing the usual Ranma storytelling tropes and devices, then repurposing them into an entirely new way.
In the case of the Ryu Kumon Arc, it was in the service of creating the best antagonist Ranma ever faced, his true mirror(As opposed to his true rival Ryoga), but in regards to Ryugenzawa, it was all about the using the usual bickering, misunderstandings and bad communication to put Akane and Ranma's relationship under the microscope and show us how much Akane both really does love Ranma, but also how much she genuinely takes their relationship completely for granted.
In many ways, Akane treats the first half of this arc as just yet another Ranma story, with a new love rival of the week, wacky side character, and an outlandish yet powerful foe to face at the climax... But where it differs so much from every other arc in the series is how Ranma, usually the focus, is effectively pushed to the sides, both by her, and the narrative.
But rather than this being treated as a wacky series of misunderstandings, we are instead shown how Ranma's and Akane's usual back and forth bickering, and refusal to just treat the other with openess and respect makes their relationship both dynamic(and with it surprisingly powerfull given how it bounces back from the worst shit immaginable)... But also very, very fragile under the wrong circumstances.
When Ranma in his usual way is angry/concerned, Akane reacts in her usual way. That is to say she gets into a completely avoidable fight with him over something trivial, in this case how Ranma(Correctly) thinks that there has to be something more to Akane's suddenly good cooking rather than just give her the compliment she so desperately craves.
It's the usual Ranma/Akane fight, seen it a thousand times before, and thousand times after.
The difference here is that rather than get into their usual rythm of sorta making up and continuing with their day, Akane sending Ranma flying once again isolates him from her, and means that her relationship with Shinnosuke and his grandpa once again takes center stage, while Ranma gets shoved off to the side.
And when Akane realizes Ranma is jealous of shinnosuke, she does the thing she always does in that situation, she rubs it in his face, because she wants him to admit it.
You'll find this very same thing a dozen other places theough the franchise.
The difference here compared to all other times, is that here, this is a genuine mistake on Akane's part, as she completely fails to read the situation, thinking it's just another moment just like it.
Just the same as always... Right?
Then after saving Shinnosuke's life, Ranma and Akane have their usual misunderstanding, where Ranma leaves before Akane can explain herself.
Again, seen it a thousand times elsewhwere.
Except this time, it's a bit different, because Ranma is taking this very, very serously, and badly... Meanwhile Akane does not in any way even consider that this was something important. Just another misunderstanding eith Ranma.
This time with the roles reversed(Which is rarer, but does happen), but still, just another unimportant thing thst will be glossed over in time.
But this time, that doesnt happen.
The breakdown of her and Ranma's relationship that Akane has been too oblivious even realize was happening reaches it's climax as Ranma has finally had enough, and decides he's gonna do the exact thing that Ryoga wanted to do, to lay out his feelings and demand she give an amswer here and now.
If she really wants to break up with him for real, he'll accept that... But if so, she will tell him that, face to face.
Of course the big thing this entire thing relies on, and is about, is that neither Akane nor Ranma is reading the situation correctly at all.
Ranma is not wrong in his assessment of Shinnosuke as by far the most "Dangerous" of his many love rivals for Akane's affection, but he believes they are much farther along on this journey than they actually are. In essence, he thinks this is the final climax of the love triangle one way or another, when it's really only about a third in.
Meanwhile Akane completely misreads the situation as her boyfriend just being jealous as usual, and completely overreacting to Shinnosuke's pressence, and so rather than try to calm him down or reassure him, she makes the choice of prioritising keeping Shinnosuke's mental state in better condition than Ranma's, rather than recognizing that Ranma is pouring his heart and soul out to her, and that he is being dead serious that this time is NOT just another argument between them.
He WILL take whatever she does next 100% seriously as her definite statement of where she wants their relationship to go next.
Which is why when she slaps him, for him, that's it.
He poured his heart out to Akane, and told her to give him an answer one way or another, and her answer was to slap him.
She doesnt want him. Simple as that.
Then, to drive the nail into the coffin even further, rather than apologize in a more meaningful way, Akane instead feebly tells Ranma to hit her back.
As if that would make up for what she just did, or be something Ranma would actually want to do.
What she tries to do with those words is to get them to go back to the dynamic they had before, the bickering, the arguments, the bullshit teen drama... But it doesnt work.
Ranma does NOT come back to her.
For Ranma, all of that was built around the foundation that Akane really did love him despite it all, as he loved her, and once that is gone, that's that.
There is no going back to what they were before. Not withouth that foundation of mutual love.
While i personally think the Ryu Kumon arc is much more solid overall in action, development, resolution and as a character study of Ranma and the Saotomes, I still find the sequence of events as Akane Tendo completely unintentionally burns her own relationship to ashes using all the same storytelling tropes and character tics and traits that the manga spent almost 300 chapters before this exploring, to be Rumiko's single best bit of writing.
While It's a shame that the arc as a whole isn't quite as good(The choice to end the big, final battle against the Yamato at a joke anticlimax was... not a good decision), this very specific bit of writing(along with Akane's love triangle as a whole) is still the best Ranma has to offer.
It's a perfect example of for all that Rumiko addmits she writes by the seat of her pants with no planning, her greatest strength as a writer by far, is that she understands fully how her characters tick and works, and how to get the best out of them for her stories.
