This is a huge speculation but because of the one day Junpei visits Chidori in the hospital where they talk about what they remember from their pasts, I believe that health is extremely important to Chidori. Junpei tells her about how he had a dream that he would become a professional baseball player as he laughs at his childish stupidity. Chidori does not respond with the same sense of humor. Instead, she responds barely remembering anything from her past.

    Junpei: When I was a kid, I had this crazy dream...
    Chidori: ...What kind of dream?
    Junpei: That one day, I'd grow up to be a pro baseball player... Pretty stupid, huh? I guess that's part of bein' a kid.
    Chidori: Is that so...? I don't remember much from my childhood. All I remember is... being surrounded by white.
    Junpei: Huh?
    Chidori: I hate hospitals...
    Junpei: Yeah, me too... ...... I'm sorry...
    Chidori: But, I don't mind that much this time... since you come to see me so often.

It's easy to then assume that Chidori spent most of her childhood in the hospital with bad health. She must have been an extremely weak and fragile young girl. The reason I like to point this out is because she spent most of her life in the hospital, and then she gained a Persona. With her new Persona, she gained the ability to heal others, as well as other living things. We see her revive a flower and a person throughout the series. This shows once again how much her Arcana matches her personality. Being weak her whole life, her Persona is able to give her the strength to live on. Although Chidori still uses self-harm methods, she is able to wander around the town freely now.

Another fascinating thing is that if you complete a few mandatory days of speaking to Junpei, you can have a scene on Thursday January 21st where Chidori can come back to life. Chidori is able to use the health that she put into the flowers, that were from Junpei Junpei every day, to come back to life. This process is called Transmagnification. She was in a state that is neither living nor dead for awhile, and shortly after her body was put away, the Doctor took all of her restored flowers and put them in the casket with her. Basically, the flowers brought her back to life because she reclaimed the life energy she once gave to the flowers. In exchange for life, she gave up her powers and her Persona, but she gained the willingness and drive to live, and another chance at a life (which shes had many chances).

You may be wondering to yourself - HOW DO I GET THIS ALTERNATE ENDING?!?! Well, just follow these few directions:
➊ Talk to Junpei on 11/06
➋ Talk to Junpei on 11/11
➌ Talk to Junpei on 11/14
➍ Talk to Junpei on 11/22
Each time you talk with Junpei, he will be really depressed about Chidori, stating how he wishes she would want to see him more. Every time, pick the option that motivates him to continue to see her and push forward with their relationship. You only need to talk to him three out of four times to get this to work. It is recommended to just talk to him on all four of these days so that you will be sure not to forget one!

b a c k   .   c l e a r   .   f o r w a r d