I struggle with the announced inability of a Pilot to apply pedal to the stop if the helicopter is yawing.
That should be a natural response....apply that pedal which is required to stop the yaw.....and if you hit the physical stop and the yaw is continuing.....then you have a bonafide emergency to deal with.
Upon hitting the physical limit of the pedal movement....you would have to assess the situation to determine the factors causing that.....and determine what actions are needed and are possible.