Arno, going by the symptoms. can I assume that this was a partial and not full envenomation.
Another factor, we always advocate wearing proper footwear when in the Bush or when dealing with venomous snakes, here is backup proof to what we teach, if Johan had not been wearing closed footwear, the consequences of this bite would have been far worse.
Lastly, Johan has most probably used this technique to demonstrate the speed of a Puffy Strike many times in the past. The lesson we need to learn from this is that we need to be super alert and vigilant at all times when handling or dealing with these animals.