The only unholdable you can avoid by low holding is the sidestep P. If you mean you can interrupt the combo by low holding, sure. The idea of this video is to show 3 unholdable setups that can be jammed together for a continuous massacre.
The idea behind it is that if you land a hit on the frame that is [your frame advantage +1], it will become unholdable and unsidesteppable. If you're caught in a setup like this, your only option is to stay on the groud or tech roll and guard. Nothing else will prevent you from getting beaten.
This setup works on the following characters: Bass, Bayman, Leon, Rachel.