Shouldn't the FDR tell us the aircraft's heading during the static runup?
FWIW, for a performance check (called MPA once upon a time, not sure about today), setting high power (at least 50% thrust, usually) is required for a specified stabilization time of a few minutes. If this were the case at TLS, and the work crew were not aware the ship was moving, then the reason for the 11 seconds delay in retarding T/L's might be understood.