Ray,
True about the hawkbill and good work in the clip.
Glenn,

indeed.
~~
When thinking about all this...if you don't see the knife, whatever it may be, you will get stabbed or cut despite being good at empty hands defense no matter what system.
If you see the knife ... and if you must stay in the fight_ it is best to keep your distance and use cover if you can while going for improvised weapons...or reach for a real effective weapon you may carry, like a pistol.
Or take flight from the danger anyway you can.
Taking on a guy with a knife if you see it, with empty hands, is never recommended because fatal mistakes will be made, inviting death at our door.
I saw a guy get killed with a knife back in the old country and that sight is printed in my mind indelibly.
If you have a knife of your own, and you are trained in its use...it is still best not to get into a 'duel' ...and try to evade seeking cover...or take flight if possible.
Even if you shoot some assailant coming at you with a knife, you cannot be sure of 'stoppage' before he closes the distance and stabs you in the chaos and under the adrenaline dump, unless you score a head shot, which is also not likely, even at close range, under the dump.