In short, Justice Berg accepted the defence, under section 43, of a schoolteacher who grabbed a child by the wrist to take the child to the back of the classroom and release the child once secure, because the child was becoming violent and there was a fear that the child would assault another pupil. The judge said that this was a good example of a situation where force could be used to control a child and prevent them from being a danger to themselves or others.
I imagine you agree with that decision.