my personal rinterpretation includes some of the following (edited for clarity now that iāve slept <3):
Rin is very aware of the fact that she is a Girl in a Shonen Anime, sheās a girl, her parents are, respectively, a dead man from Suna and a chunin woman of no particular renown. After the third war began, she believed she'd be killed outright because of her parentage, partially perpetuated by her classmates (rinās dad is from suna, weāre at war with suna, rin is going to die because sheās from suna). Her mom specializes in solo courier missions through difficult terrain, leaving Rin alone for long chunks of time in naruto-typical child neglect. (Their apartment is full of spiderwebs clogged with dust, since rin doesnāt clean unless someone else is coming over.) And if her gender and background werenāt enough, sheās not naturally gifted as a frontline fighter.
Rin is expendable. Sheās canon fodder. She understands this.
She tries to circumvent this by curating herself as a palatable nice girl and useful soldier (medic), playing to her strengths while mimicking the Only Woman, Tsunade. the strength she builds here is acceptable. girls are healers, girls are kind, becoming a medic is an acceptable path, a safe path, a path that is not odd or transgressive in any way. She dilutes herself, presenting a person who does not complain or want or grate on anyoneās nerves. She does not speak her mind. She does not cede her position as an unassailable ideal. When she begins this, her aim is to survive (rin is such a nice girl replaces the gossip about her father. if you stand out, you die, so rin folds herself carefully into the safest box she can manage.) she makes Nohara Rin a good girl, and a soldier worth keeping alive.
(she neglects her taijutsu and non-medical ninjutsu after she abandons that path in a sort of self-fulfilling prophecy. she can't be a failure at something if she never puts the effort in to learn it, which I think also played a large role in her continuing friendship with and encouragement of Obito, who wasn't naturally gifted at anything but never stopped trying: a quality and privilege she envies.)
By the rinnening, Rin is miserable because sheās spent her life exemplifying an unattainable ideal rather than living.(despite the fact that sheās very nearly succeeded). She doesnāt know who she is, because sheās built her life around trying to become someone the world acknowledges as a person, rather than a statistic. She resents herself, the idea sheās created and her ārealā self for failing to live up to it. Rinās life has been so consumed with creating Nohara Rin, that sheās killed herself in the process. Rin was always going to die, and in attempting to survive, she killed herself before she could die.
Part of her enduring misery is also that none of her interpersonal relationships are āgenuineā leading to a buildup of resentment over the years. She doesnāt speak out when things bother her, choosing to ignore problems rather than face them and potentially break her relationship and ācauseā grievances. Even if she knows intellectually that this tendency means no one knows when things bother herā-itās hard for that not to build. She wants to be understood and seen on an unconscious level, but sheās overshadowed by the idea of herself that sheās constructed, and cannot let go of it enough to be seen. She thinks herself unlovable, because sheās constantly measured against her ideal and found lacking. Rin is a ghost haunting Nohara Rin, the ideal, a concept thatās grown blood and bones as sheās turned insubstantial.
She no longer feels the same drive to survive out of a sincere desire to live, but is instead motivated by a desperate kind of endurance. She feels consumingly empty, a kind of hollow pit inside her ribcage that lingers without respite in the periphery of her awareness. She pretends to want a future, and she still refuses to die on someone elseās terms. At the end of things, if she could believe in a future for herself, her ārealā self, she would want to live, but! Sheās trapped herself. She canāt see a future for herself, rather, she sees a future for Nohara Rin, where she continues to wither away without notice.
When she kills herself, consider that Rin has a bomb inside of her and that she can't tell anyone else about it. She's a medic! she's not supposed to be a frontline tragedy!! she's supposed to live!!! this isn't fair.
So Rin believes this is going to kill her, no matter what. She does not trust minato or anyone to save her because no one saved Obito at Kannabi, and this fundamentally broke her trust in her teacher's ability to save anyone. (they are soldiers first, and she knew this, but obito was a clan kid and a boy and compared to that rin is no one) Rin is going to die, going to become some useless casualty who no one will save, and what she wants is to die on her own terms. what she wants is to not be forgotten.
(and, frankly, if she does live, she sees becoming a jinchuriki as a fate worse than death. Nohara Rin can never be a jinchuriki, thatās antithetical to the idea of her, rin is cute and nice and lovely, kind, sheās a medic, she has excellent chakra control, sheās not a brutish living bomb, something to be afraid of and scorned, with corrosive chakra that would burn, rather than heal. She is angry and she is scared and in another life maybe she would have learned to live with the reality of being a jinchuriki but in this world? She has to die. If she doesn't, all her work has been for nothing. Years of sanding herself down for consumption are worthless. Itās all for nothing. She has to die before Nohara Rin can be ruined.)
If she dies in the course of battle, if an enemy kills her, that's routine.(she'll be the canon fodder she's desperate to avoid becoming) (she'll become a statistic) (they'll bury her body in the corner of a graveyard and no one will visit her) If Kakashi, who found his father dead on the floor, is the instrument of her suicide---he will never forget her. He'll grieve her in the same way he grieves Obito.
So: I'm going to die. I refuse to die like this. So she, (cruelly!!) traumatizes Kakashi so her memory will live on forever as a tragedy instead of a statistic.