I saw some "graphics" in my Edged Weapons class at Gunsite. That's when I realized just how dangerous a knife can be. It doesn't have to be a long blade either; looking at the pics, none of the wounds appear to be over three inches deep.
Interestingly, although there are signs of bleeding, the wounds themselves have no blood in them whatsoever. I've seen that before in knife wound pics.
It also makes me wonder if the wounds, as bad as they are, would be more incapacitating than a gunshot(s).
It is absolutely amazing what can be done with a knife in a flash of time. I got a video from Fist inc. - the holster maker and I was actually frightened by the brutality and speed with which a knife can be used.
I think most of us kinda visualize a knife as a stab and wait tool, but a semi-trained person with a knife could inflict at least three deep (1 - 2 inches or to the bone), broad (a foot or more) slashing wounds per second. How long does it take you to draw and fire your gun? Scary huh? It ought to be.
Knife techniques don't have to be directed to the torso to be effective either. If they slash the tendon of the bicep just above where it connects to the forearm, you won't be able to use that arm.
Another, is a thrust into the arm pit to sever the artery that is located there. Knives are dangerous.