Escape from the Tiger's Mouth - S1.E11

When a colleague has to rush home to care for a sick child, their home-room teacher declares a self-study hour, which moves to the gym to get an early start on the next period's PE class. Meanwhile, Yanagi and friends kibbutz from the balcony, with Yanagi hoping to get easily-marketed photos of the girls in their gym clothes. The time in the gym turns into a deadly game of dodge-ball, with most of the class laid out by brutal throws to the face. To bring peace, Torako suggests trial by champion --- Suzume vs. the teacher.