In the handgun class this past weekend I got my first demonstration of why the old adage about bringing a knife to a gun fight might not be true in all instances. The instructor took a rubber knife and gave a student a toy gun, which the student holstered. They stood a bit over 21 feet apart and the instructor told the student to draw before he got to him with the knife. Even with the knowledge that the instructor was going to come at him it took him three tries to get the gun out before the instructor got to him, and even then he would have more than likely missed his shot and got cut or stabbed.
The other demo the instructor did was to take a large rump roast and wrap it in a t-shirt. The whole bundle was about 1 foot long and anywhere from 4-6 inches thick. After taping this bundle to a stick for safety he then took a standard folding knife with about a 3 inch blade and slashed the meat with it. The knife nearly severed a large section of meat off. The cut was towards the end of the bundle, so probably 4-5 inches thick where the knife cut it. So, if the bundle represented your bicep then it would have been severed clean. He then took another folding knife with a 1 inch blade and did the same thing. This tiny one inch blade cut a 4 inch long gash that was at least 1 inch deep.
With either of these two blades a cut to the right part of me and I am done. This really brought home the point Gary Brommeland was making, in a different thread, about not letting someone close to within 20 feet of you.
If you have already drawn your weapon you have the advantage, if not you are done.