In order to avoid this Kind of situations We do have in maintenance some safety nets.
Every 2 to 3 years depending on the company, there is a Simulator cession with all the Problems you can Encounter during a run.
But above all, even if you pulled tons of CB's, you have checklists for running high power, AMM procedures and again tons of warning as preamble of any maintenance Operation,( particularly when chapter 70 to 79 is involved).
There are safety precautions you should not even think about shortcutting like chocks, park brake, or if no park brake Holding the Brakes (mandatory on Airbus as parking brake cannot hold hign power).
On some aircraft you have to put the EDP on (not automatic) and electric pumps as back up...
I did hours and hours of high power run on prop and jets aircraft.. You have to Think and use checklists, it is so easy to Forget something.. And the stress is 99.9% seft induced, never in my carreer a Boss told me to not use checklist or make shortcuts to go faster.
But I believe I would be very upset if I would be the Boss of the guys in CPH...
You know in the past there was nothing, and after a few in/accidenst the authorities came with rules and procedures. They are always People thinking they are better than the others, but These rules are really helpful that you can oppose them in case of time pressure from you Boss...
And they can save lives and aircrafts...