Obviously I'm no knife-throwing expert, but I would think you could get a LOT more speed and penetrating power with an overhand throw versus the underhand throws Jaimi and the expert were using.
It seemed like they were both concentrating more on hitting the little bullseye instead of really
doing damage to someone with a knife.
Obviously with a faster throw you still wouldn't be faster than a speeding bullet, but you'd still be inflicting serious damage on your opponent (because, as has been said, it's not like you're going to drop dead the second you get shot). And even with a gun you're likely to be shot anyway, so it's not like you're avoiding much with that option.