Instead, after applying full thrust, he had taken his paw off the thrust levers and allowed the still engaged Auto Throttle to retard the thrust levers a second time.
I wonder why. Perhaps he needed two hands on the control column. After all, if the trim was full back, and they were very slow, he probably needed two hands to stop the thing doing a loop.
From that point, this was far from a normal goround and it is quite reasonable to expect that some of the "normal" things like hitting the TOGAs would get missed. It was probably the first thing they knew that anything was amiss! "OH MY GOD!!" would have gone though all three pilots minds. Do you reckon the Captain would have had the wherewithal to say "I say old chap those naughty thrust levers have come back to idle, please reinsert them in the forward-most position as I am fully occupied trying to fly this mother out of the stall with two hands!"? I suspect that at that point, it was "all over red rover" and lambasting the other occupants, especially the safety pilot (probably an FO), for not doing anything, is stretching the friendship a bit. They would have been in total bewilderment.
The captain did one thing right - he didn't flick it. That would have killed everybody.
One suggestion. We have autocalls for all manner of problems. What about one for "Airspeed" when the speed gets to Ref-10 unless the wheels are on the ground?