We focused on gedanbarai and maegeri/gyakutsuki combos for much of the lesson - over and over to the point of exhaustion. It was the first time I think I've ever seen Sensei have mercy; eventually he must have noticed we were flagging despite our best efforts, and gave us a short breather.
I love that type of session, though. Repeated practice is the only way to improve. It's funny how the school system has turned away from rote learning so completely - my experience in adult life learning Japanese and now karate have told me that rote learning is vastly underrated. It requires motivation, so it may not work brilliantly with all school kids, but there is certainly a place for it. It's very enjoyable too, in its own way, to just tune out and let yourself go with the flow, almost ceding autonomy for a short period.