Not perfect but interesting. If he had thrown a simultaneous counter strike to the face the battle would have been easier.
But the shock knife does bring an element of danger! Something we should consider in our knife training.
The video shows a defense which is based on strength, which can work, but only for those who are least as strong as their attacker. In Krav we try to use simultaneous counter strikes to weaken the attacker, and continue striking until said attacker drops his weapon.
The guy in the video made it work. I simply think the krav defense to the attack is simpler, easier, and more intuitive. But, that being said I love the idea of working with a shock knife for a scarier training experience.