Work with a short blade.
Just some notes I copied from other peoples' discussions.
To display the knife rather then just using it indicates more interest in assertion than stabbing. If you want to it is easy enough (I imagine) to stab somebody without ever being seen, if you choose instead to show the knife you are choosing to call attention to yourself and actually making it much more difficult to stab anybody.
Get your training partner to put the tip of the blade on you body then push slowly in one direction. You should breath and move so that the knife is allowed to continue on it's way without being deflected off it's path. Do this over and over again, with the knife held at every angle you can come up with including the one you are having difficulty with.
The reason for this drill is that it allows your body to learn how to escape the stab when you have not seen it coming. It literally learns to work on contact with the blade.
When you are successful at working with the weapon against the body then have your partner thrust or slash in a slow fluid manner. You should breath and escape the attacks with as economically as possible, with good form and without relying on yours arms and hands to deflect the path of the knife. (There is that kind of work, but this drill will not be nearly as useful if all you try and do is swat the knife aside.)
Make sure your movements are at the same pace as the attack. If your partner is moving slowly and you engage warp drive to avoid it what will you have in reserve for a fast attack. With this sort of drill it is about moving to where you feel safe. If you don't have this feeling when you are moving out of the way of an attack your movements will be clumsy and throw out your form.
These two drills will teach you about working against any angle of attack. You can add to them when your confident in them, by working against your partner simultaneously with your escape of the knife. Again do this at the same pace as the attack and you will learn to work against all the angles of attack and not just the ones on the video.
The grip matters negligibly if you are moving not trying to work the knife. Move your foot first and be patient. Work the body not the weapon. Move yer frikkin' foot man! Breathe! Ahem.
Try with your eyes closed first to truly see where your body says to go. Did I say keep your eyes 'up' and breathe and step first instead of contorting from the point of contact?
1) Don't try to catch the blade. Redirect then control.
2) Don't be weapon fixated. Work against the man.
3) Attack him with everything. He has lethal intent so should you.
4) Be aware of environment. He might have friends with knives.
Consider that most of knife work taught out there- in Filipino, Indonesian, Chinese, add your own flavor, is based on assumption of resistance (blocking, grabbing, etc.), or in best case scenario- not so subtle deflection- which implies affecting, changing attackers movement. In short- reaction initiated by fear is expected. By slightly changing the positioning of attackers target (your body, or its part)- considering distance (move in or out), angle (shift sideways, or vertically), you either avoid the attack while simultaneously being in position to do your work, or force the change in attackers action (less likely considering that we are talking all out, full throttle, fast and furious action- even if its short slashing work aimed at your extremities- as is common in South East Asian arts- as a precursor to get to the core- your body mass, neck, etc.), or transfer his consciousness from where it is at now (most likely 50/50 split between his blade and its destination- you) to new area- such as re-adjusting his balance, regaining solid footing, or 100% of his being wondering "where the fuck did he go???" Either way you are not any more reactionary- you are in the lead and he is trying to catch up. Which gives you plenty of immediate opportunities to end everything.
Defence against knives is the base paradigm of all defensive movement work.