Re: causing no (serious) harm
The idea that the intent behind an action has an effect on the morality of that action is as far as I know an idea that originated from Roman Law and was adopted by Christianity. Hence, we give lighter punishment to those who show remorse.
So I have serious doubt that for O-Sensei the intent whith which you break an arm would make any difference. You broke an arm. Period. If that was without the intention to do so, you need to train harder to improve the control you have over your technique.