I don’t know a ton about guns, but I know enough that a standard car door isn’t going to do much to stop a bullet, especially not something coming out of a rife. Now I don’t know if your standard police cruiser has slightly tougher doors – I assume they’re at least a little bit armored. Every movie and TV show ever has cops popping out of their car and taking cover behind the doors. I guess it’s better than nothing even if it isn’t armored as it kind of hides you, but even if they’re armored like battleship plating it seems like a good way to get shot in the feet.
Most cop/detective/etc show have people being moderately intelligent about using cover, but as soon as you stray anywhere near action hero territory, it seems like the good guy never wins because he uses his environment tactically, he wins merely because the bad guys can’t hit squat. How many times have you seen a hero running down a hallway or across a clearing while multiple people fire automatic weapons at him? Can you think of a single scene like that where the guy even tries to zig zag? No, he runs in a straight line, usually in slow motion cause it looks more dramatic. If no one firing at him had ever handled a gun before, ok, then I’d buy that the hero could escape unscathed, but usually he’s up against mercenaries or soldiers of some sort, and presumably they’re familiar with their weapons.
I may need to tweak Peggy’s dialog a little on this page as “Firearms 101” isn’t the name of an actual course in the military. Also I’m pretty sure “technical manuals and regs” isn’t the right lingo either, but I wasn’t sure how to phrase it. Asking about this stuff on Twitter gets a lot of different answers as it seems every branch does things a little bit differently.