Old-school thinking held that if a tourniquet were used on an extremity wound, the injured person would lose that limb. That has been shown to be incorrect, and tourniquets are now in the first-aid kits of medics on battlefields and streets worldwide.
Rob Pincus discusses zeroing your home defense long gun optic and why the normal rules of The Plausibility Principle are trumped by the efficiency of zeroing your rifle for much further distances than you would most likely be using it.
Student alert! If your defensive firearms instructor is not giving you an integrated system of firearm manipulation techniques but rather a set of unconnected techniques that don't integrate well together, don't reinforce each other, and don't contribute to your efficiency by being consistent with one another, you need to challenge those techniques.