Bulletproof Vests Are Magical Force Fields
Somehow your best laid plans have gone awry, and now a bunch of Libyans in a Volkswagen van are out for your blood. They plan to shoot you repeatedly with their AK-47s, but you have an ace in the hole: a bulletproof vest.
In the real word, the vest that protected Back to the Future‘s Emmett Brown from the terrorists would only have been useful for its ability to keep all of his bits in one convenient (for the mortician) package. In fact, despite an additional 25 years of armor development, no body armor today would be able to protect Doc from that kind of assault.
Our troops do have their own body armor, meant to protect against that sort of thing. It’s much heavier and more rigid. But even it’s only rated for effectiveness at further than 14 meters distance. When police wear body armor (45 percent do not) they don’t tend to wear full military body armor. Probably because it weighs 33 freaking pounds and costs thousands of dollars. Since less than one percent of gun crimes involve military-style rifles, this is generally a pretty safe trade-off.