@Elon-chan I guess you failed to comprehend the statement that the MC made when he said that "Sensei tasked me with something to do..." therefore, the MC will be within school grounds.
This chapter reminds me of the HSDK chapter where they did training at the water park and Miu went up the water slide. Then Kenichi and Ma Sensei were fighting over who gets to follow Miu up the slide to get a peek of her lady bits 🤣