I'm always amazed at the folks that always want to put the great "what if" into the mix. Yes you focus on what will potentially KILL YOU. Biomechanics has a lot to do with training and technique concepts. Just because the focus is on the weapon, dosen't mean that you stay in one place and open yourself up to other possibilities. You focus on and as you attempt to push/grab/trap the attacking limb, you also deliver a strike in the process. Me personally, I'm going right for the throat if I'm in range or for the knee if I'm out of that range. Then and only then do I attempt a disarm or just break the arm, whatever comes first. Understand here and apparently most folks don't, we're not trying to deal with the infamous "trained knife fighter" that everybody likes to think there going to face. We train for the thug in the street, who uses a knife but is not the Zorro of folks imaginations.