The guy who mentioned experience took my line. I'll add knowledge. Experience and knowledge (and brains, of course) will help a lot here.
E.g., I read a paper by the FBI once on gunshot wounds. Long story short, no, people don't generally die instantly when they're shot. In fact, they don't even usually fall down (much less get thrown anywhere) - that's more often a psychological, rather than physiological reaction. In fact, it often takes a hell of a lot of bullets and bleeding for an angry perp to go down. Usually, it's a direct hit to the spine or brain that results in an instant kill. Otherwise, people have to bleed out or bleed to unconsciousness before they go down. Which can take anywhere from 8 seconds or so for a really nasty hit (say, the heart), up to several minutes. 8 seconds is an eternity to have an angry person shooting back at you.
A scene that dealt with all the interesting parts of that paper would be unlike anything I've ever seen.
Of course, then we have to consider the "reality isn't realistic!" trope: people are conditioned by movies to expect unrealistic tropes and are often upset when a movie "unrealistically" breaks these unrealistic conventions.