After the first dojo, I would have noticed the trend, and just said "I have come to retrain as a complete novice, will restrain my power to the absolute limit, and face this training as a complete weakling." That should have worked on anyone, even if they come up with some reality bending explanation for how he can actually Clark Kent himself.
Edit: or go back and tell Fang that you don't want to hurt anyone, so you've come for some technical training, to no longer rely on brute strength.