Further proof that marriage is EVIL! 
Forget the Past, his fate and fame shall be
An echo and a light unto eternity!
Quicksand
That seemed like a pretty bland reply to the question.
Don’t know about that. I regularly see cases where a person died from brain injuries sustained from only falling backwards and hitting the back of their head on a hard surface. Starting from c. 5 feet off the ground, the nugget will reach potentially lethal velocity by the time of impact.
The instant death from such a fall is what’s more unrealistic.
When any sort of disaster strikes a city or town the first thing the locals do is go to the towns Welcome sign and cross our the city name and put WELCOME TO HELL.
Falls are a common form of accidental death./The wedding is perfect in every way, but never happens.
True story:
When I was working on my high school’s yearbook, the staff stumbled on one from another school that was in our library.
It contained a tribute to an alumnus who had survived a tour of duty in Vietnam and returned to Podunk to marry his childhood sweetheart.
While the happy couple were about to take their vows, the groom tripped on the carpet and fell. He hit his head on something hard (the steps to the altar, I think) and died instantly.
We all had a good laugh over that one! 
I remember an episode of Rockford Files where he’s chasing some guy through Hoover Dam (or a similarly large dam) and finally the guy being chased has to stop and sit down on some steps to catch his breath, and Rockford comes running up behind, equally out of breath, clamps a hand on the guy’s shoulder and wheezes “Gotcha!” and then they both just sit there panting. It was hilarious.
There was at least one episode of Cannon in which William Conrad (a hefty dude fer sure) had to lie down and catch his breath after chasing a bad guy.
My friends room mate, was punched, fell back hitting his head on the curb and he died. I didn’t know him very well, he was kind of a douche.
Quicksand happens in real life. My horse and I fell into some in a rain-saturated gravel quarry when I was 14 and although we were able to (separately) swim to safety, it scared us both to death.
Well, that right there shows you the difference between real quicksand and TV quicksand. Nobody ever swims out of TV quicksand. Once you’re ankle deep in it, you’re a goner.
Where was Lassie?
Just saw Bloke on the Range pull off hitting a target from 90+ yards with a black powder hand gun. I would have to ask the husband which video it was on, but I think it was on Gun Jesus’ channel on youtube. I would imagine that those two shooters could pull off nailing someone with a handgun from a great distance. [in respect, I can only manage something like that type of shooting at around 45-50 meters]
They were considering Conrad for Matt Dillon. He was the voice of Marshal Dillon on the radio series. But he was a bit too hefty even in the mid '50s.
Radioactive components spill out causing giant mutant animals to run amok in the movies. Real life, not so much in real life (ho-ho). Can you imagine a 20 foot tall kangaroo? Ha!
I was caught in quicksand as a 4 year old, with limited swimming ability. Thankfully my dad was close by and managed to locate me underwater/sand and pull me out. I have vivid memories of going down, eyes open but unable to see anything.
Also - on the unrelated topic of toilets, one rather famously makes an appearance in Pulp Fiction, when Vincent Vega is caught with his pants down by Butch Coolidge.
Humans often can get out if they don’t panic and try to lie as flat as possible. Horses often die if they don’t have someone to pull them out. Heavy bodies, skinny little legs. I know of two local horses who would have died (of exhaustion and shock probably, not drowning) but for heroic efforts to save them. Same very wet year, different areas of the county. Not really quicksand just very deep liquid mud.
I can only assume we’re about to find out.