Despite it being a shoujo, Nakamura always pushed the bounds in her work. I mean Ren used to beat people up and that indirectly lead to Rick's death. We can see the type of psychological impact it cause him. I don't doubt the notion that what's-his-face drugged Saeko. But I'm confused as to why?
Sure there is that court case, but that's a whole four days away. How could drugging her so far away from the case be beneficial? Then there is the idea of him raping her. This has 3 outcomes: 1) Saeko manages to wake up in the middle of him doing it, or 2) she wakes up afterwards and he gloats, or 3) she takes a pregnancy test later to confirm.
Despite that, even if he did impregnant her, she still wouldn't know. I mean most pregnancy sticks can't confirm until 2-8 weeks of pregnancy.
And even if he did rape and impregnate her, couldn't she go to the police? Rape is a serious matter, especially if he drugged her. Plus, the police are more likely to believe a female in a rape-situation (which isn't generally a good thing, mind you). That would surely get him kicked off the case.
I don't know. It could be that she got a fever and passed out and Nakamura wanted us to freak out.