Knife vs Gun - The 21 Foot Rule - Great Demonstration

Why cops shoot people holding a knife instead of using a taser. If a persons reveals a knife and he was already closer than 21 feet, you can't holster you gun and switch to a taser that fast. Legendary Eskrima martial artist Dan Inosanto demonstrates how dangerous an attacker with a knife can be to a police officer inside of 21ft. 21ft can be closer then you think. Would you have time to draw a weapon respond to an attack? This can also be useful information for citizens who can legally carry a concealed firearm.