Ok... of course I stand to be shot down because I wasn't there and shouldn't judge. I am not judging, simply asking a question:
Would any pilot feel particularly comfortable doing engine runs relying on the park brake? From experience, I would prefer to hold main brake pressure instead of relying on the park brake, and would guard the thrust levers at all times, ready to retard.
11 seconds elapsed between the first sign of aircraft movement and retardation of the thrust levers.
Not sure if the 'commander' was a ground engineer or a pilot, but as a pilot I would try to avoid 'heads down' time if I was in control of the aircraft during an engine run. Let someone else look at the instruments...
Are ground engineers encouraged to display similar caution?
VI