I tend not to post, and even more rare is me agreeing with crab....however, I have to agree with him 100%.
Any number of events, most of them completely outside the control of the pilot, could have turned this 'exercise' into a fatal accident.
I can immediately think of a similar situation where an instructor, trying to impress a student with how 'skilled' he was, and how much 'fun' can be had in helicopters managed to kill them both.
The first priority of any instructor is to impart, above all, a sense of self-discipline and a mature approach to flying. Without these any new pilot is an accident waiting to happen.
Totally unprofessional imho