We can only speculate why he has only run it at full power for less than a minute at a time. No sane person would try a first flight with that amount of testing on any engine, let alone an experimental one that so many are highly dubious about.No doubt. Plus several friends with fire extinguishers and saws.
I think the real question is whether he'll find someone who will take on the first flight. I just can't see anyone who understands the situation taking that on.