The female student (Sakuragi-san(?)) is chloroformed by her teacher. Next, the teacher pushes her off the roof while she's unconscious.
Source: https://mangaseeonline.us/read-online/Sherlock-Bones-chapter-4.1-page-1.html
Kozue Ohta is chloroformed by some bad guys and carried to hidden place. The wake up scene happens in chapter 15.
Source: https://mangakakalot.com/chapter/goumon_tournament/chapter_12
Original name: Otome Gēmu no Hametsu Furagu Shika Nai Akuyaku Reijō ni Tensei Shiteshimatta
This is a manga adaptation from light novel series. In this chapter, the main female (Katarina Claes) is chloroformed by some mysterious guys. All she could say in the last scene was "what is this sweet smell?" and "why do i f...
Some time after overdosing and being chased by monstrous dogs, Brenna Campen faints, is saved by her lover, the Manhunter, and is later almost sacrificed.
Source: ComicOnlinefree.com