Whenever a character in a movie gets stabbed with a sword, tossed in a flaming pit, or garroted with a live cobra, we all know what to expect. We, as an audience, are jaded. We've seen it all before; we can practically tie a snake-noose in our sleep. But that doesn't mean the reality looks anything like the movies. For example ...
5 You Can't Sink In Lava
New Line Cinema
Falling into lava is the worst way to go: It's all the most awful parts of drowning and burning mashed together like the devil's slash fiction. But in reality, it wouldn't be anything like that. Surprisingly, lava is really fucking hot. We're looking at temperatures ranging from 1,295 degrees F to 2,282 degrees F when it first breaks the surface. A bed of lava is a giant liquid crematorium that is unlikely to gulp you down, if only because you'll burn to death first.
But even if you cannonballed into a volcano wearing a heat-suit -- because fuck cancer, you're going out awesome -- you still wouldn't drown in it. Lava is over three times heavier and denser than water, with at least 100,000 times the viscosity. It's borderline impossible for a human being to sink in it. You wouldn't dramatically sink like Arnold at the end of T2 -- you'd just shatter and burn up so quickly you wouldn't have time to give a thumbs-up, much less the elaborate double bird you've been practicing.
4 Suffocating Someone Takes Forever
The Weinstein Company
Suffocating a person is a lengthy, arduous process. It's the "doing your taxes" of murder. The point where the movies tend to call it a kill -- right as the victim goes limp -- is only just the start. In reality, going all noodly only indicates that the victim has passed out, and if the killer stops suffocating the victim then, they're in for a surprise: The body automatically restarts breathing as a reflex.
"Yeah, I'm really having no trouble at all breathing around this pillow, chief."
This restart period varies on a case-by-case basis, but it takes the body roughly 15 seconds to use up the oxygen in the blood. After that, the clock starts ticking: A minute without breathing destroys some of your brain cells. Three minutes and you likely have serious brain damage. After 10 to 15 minutes, you're generally fucked -- unless you're one of the rare cases that survive after 40 to 60 minutes without breathing. Unless the killer has brought a sandwich and a book to read, they're better off flicking the victim to death.