The girls performed various songs for the students of the institute. However, during "Ticket", Hyuna noticed that one of the audience members was trying to film up her skirt! As soon as her part was over, she came to the back and glared at the person, and told the other members around her (check 1:45 in the video above). She can be seen mouthing, "??? ???? ???," or, "(He/She) is filming our skirts from below."
Not only that, after the song, she went up to them and told them to stop, bringing their shameful deed to light in front of every one else. (11:17 in video below)
It's not every day you get to see a female idol group member stand up for herself like a boss, so this is definitely refreshing to see. You go, girl!