Showing and practicing some reps in slow motion is a good way to build confidence and get beginners to learn and improve at an accelerated rate. When you break things down slowly you have to be more conscious and deliberate with your body mechanics and you get to observe and feel the attack, rather than just “reacting” during training and not knowing what you did. To keep the students safe while pressing their comfort zone, aggression, contact, and resistance should be increased as proficiency and skill increases,rather than going "full-bore" without having built a platform of relevant drills leading up to the higher-speed training.
Train smart & stay safe,
NOVA Self Defense