ABS is able to disengage your brakes even while the pedal is fully depressed, the old-school hydraulics are connected to ABS that can release the pressure so that the brakes disengage - that's what it does during normal operation. If it would intentionally release the brakes and keep them open instead of "pumping", there's nothing you can do.

The same applies for power assist - it's quite powerful; steering at high speed is possible but quite hard if it simply turns off; however, if it would be actively working against you (and do it suddenly without any warning), it's likely that you wouldn't be able to turn it back until you'd already smashed into the opposite lane.