Not very original from Koreeda, also last third completely changed pace from drama/thriller to his typical social drama, I wish the whole movie was shot this way.

Though I still don't understand why was the teacher sorry after finding their hidden two names in the work, after all he still didn't do anything wrong, so what was he sorry about?

And I still don't get the urgency why the boy jumped out of the car.

The ending is quite unclear, did the boys survive or died (I guess judging by the white light and missing fence they died), same with teacher on the roof (which was not hinted at all).