True, but with a caveat. One might be tempted to disconnect RTO when in that scenario. Accel/stop calculations have been made using RTO; plus I would hazard the guess that while 2 great size 13's stomping on the brakes, such that your backside is off the seat, will cause your nose to be pressed hard against window, when you start trying to steer with same said piston pumpers you will then relax the pressure on one or both of the pedals and revert back to stopping performance less than max and possibly less than the RTO you've just disconnected.
Further, why is foot pumping pedal pushing called 'manual' braking? Which part of the hand is involved?