In most autobrake systems, the level of RTO deceleration is slightly higher than the Max landing selection.
RTO autobrake is designed for safety, not comfort; the deceleration will not generate the emotive descriptions or injuries as you imagine.
MAX auto will initially - briefly - appply max hydraulic pressure to the brakes, but then try to maintain a constant deceleration (14 f/s^2 above 80 kts and 11 or 12 f/s^2 below, for Boeing. Don't bite me if the numbers are a bit off).
RTO auto will simply apply max hydraulic pressure. Deceleration then depends solely on a/c weight and runway conditions, and can be "violent".