This is when he pulled the thrust levers all the way back and pushed them all the way forward again. (The CVR records this as three clacks of the levers moving across their detents.)
Why would he pull the throttles all the way back? I'm not an Airbus guy so I'm curious as to the reasoning.
Jet engines decelerate very rapidly, and if there was any RPM above idle prior, that was undoubtedly lost and that would cause/contribute to a long engine accelerate time.
Time to get the engines spooled up was one of the critical problems on that flight.