Need some clarification and it's been awhile since I've seen the anime. I THINK I remember this was mentioned earlier, a dozen pages back... somewhere... but I don't really want to dig for it. Sorry.
Spoiler for Rika, the manga, Hinamizawa Syndrome:
* Rika's syringes from Watanagashi/Meakashi-hen, manga
During Rika's confrontation with Shion, in the syringe contains the suppressing drug, C120 (improved version of C103). If a person is not diagnosed with the Hinamizawa Syndrome and are injected by the C120, do they grow weak and immediately enter L5 state?
The manga shows Rika scratching her throat out after the injection and after stabbing her throat out. I'm not sure how she had the strength to do that... o_o or is some of that apart of Shion's hallucinations?
* Rika, the Hinamizawa Syndrome
I remember in one of the TIPS that she was asking if Satoko, everyone, and even herself had the Hinamizawa Syndrom. Her father answered with a yes. So, is it possible for Rika to show signs of the Hinamizawa Syndrome and we just haven't seen it happen? (other than being injected)
* Rika's deaths
Rika can only remember what she sees, so that is why she remembers her suicide and torture in Meakashi/Watanagashi-hen. And I guess the school exploding in some worlds such as bad end Tsumihoroboshi-hen for the DS and Yoigoshi-hen.
How is it that she remembers that she was disemboweled with her intestines drawn out in worlds where she's killed by Takano/Yamainu when she's drugged to sleep? Or was that a mistake in the manga? I believe she describes the process in the Himatsubushi-hen manga.