"...very few people know what it actually sounds like
to stomp someone's face in an elevator."
A Salon article talks about the sound effects for a scene of violence in an elevator in the movie Drive:
According to Mark Berger, a multiple-Oscar-winning sound editor who now teaches at UC-Berkeley, each violent impact is orchestrated like a musical chord. An editor might start with a thumping base note, he says—the sound of a 2-by-4 being smacked against a side of beef—and then add in some upper frequencies with a bundle of dry twigs being snapped or a plastic cup getting broken. Then he'd finish off the effect by filling out its mid-notes with something gloopy, like the sound of a ripe melon dropped on cement. By tweaking the proportions of these ingredients, he can build something dry and tough, or moist and oozy...The Sounds of Violence, Slate>>
The makers of Drive weren't trying to make the sounds of violent impact seem realistic. Like most sound editors, Bender says there's no clear relationship between what you'd hear in a movie fight and what you might hear in real life. Since very few people know what it actually sounds like to stomp someone's face in an elevator, the audio for a movie beating has to come from a sound editor's imagination. Soundtracks may be even more stylized and coded than on-screen visuals. "The criterion isn't authenticity," explains Mark Berger, the Berkeley professor. "It's perceived authenticity."