So... if I understood your posts correctly, what you are trying to say is that you have this fanfic fantasy of Tomoe finding out that MC used sleeping pills on Sheila at the beginning of the game, so she replaces them with placebos and takes revenge on the MC... right?
Ok, then:
1) The MC stopped using those pills a long-ass time ago, so for her to find that out, she would have to first find out that it was the MC who took her pills, so you are skipping a few steps. She would not just suspect rape by knowing he took her pills after all.
2) For her to realize what he used them for, the MC would have to use the pills again and be caught in the act, and at this point he doesn't need them anymore. Sheila has been a willing partner since a long time ago.
3) By how the game has been going at this point, more than angry, Tomoe would be jealous of Sheila and maybe try to insinuate the MC to do the same to her, only to pretend to take the pills, be asleep, and let herself get fucked by him. She doesn't seem currently either interested or smart enough to take revenge, just hungry for MC's dick.
Also, first they were "supplements," then "anti-inflammatory pills." You need a better translator, man.
And it was Sheila who took her dildo to mess with her, not MC.
That is at least what your first post seemed to imply. As for the one I'm replying to, same thing: she would not be out for revenge because the two were having sex; she would just be jealous, like with Catherine.