Within a split second a trained attacker could lunge the blade between your ribs, throat or any other part of your body, even your hand.
If you try to jump backward, you would not have the time and if you try to turn to the side, he could stab again to the side immediately without even moving his body after he landed on the first lunge.
The long blade provides an extension to the hand and the tip of the blade provides immediate control and reach at the same time he lunges forward.
Therefore you need to execute the most efficient defense to this most efficient attack and consider how to limit his follow up options with an additional stab or a follow up hand strike or a kick.
Currently there is not other Self Defense or Martial Art System that has the most efficient answer to this attack but Pure Krav Maga! It is unlikely that anyone else would come up with a new solution either because there is only one most efficient way to attack and only one most efficient way to defend.
Of course you could end up in a different angle and you will have to adjust, but considering the theoretical equation of efficiency, the front stab and the Pure Krav Maga respective defenses are the most efficient attacks and defenses available in the human market!
Pure Krav Maga Knife Techniques