I was the one that started the deaths onstage. I was referring to only murders onstage. But, the discussion of deaths by other causes is interesting. And the Only Murders in the Building death was one I was thinking of when I was going through different movies/tv shows with the murders onstage.
In re: Dick Cavett—
I wonder how often in real life someone has to exit a perilously high room in a skyscraper, slide along on the convenient but thin ledge outside the window, balance around a sharp corner and then somehow get through the unlocked window of another neighboring apartment/office? I am guessing not so often at all.
How often does a cop show up to a bachelorette party in response to a noise complaint, only for the attendees to mistake him for a stripper in a cop costume?
In films and TV when a room includes an old fashioned radiator, someone will eventually be handcuffed to it.
Admittedly, I don’t hang around much with cops or crooks, but in the movies, they spend a lot more time in strip clubs than most of the people I know.
In school I do not remember teachers yelling out the homework assignment just after the bell to end the class rang, with the added warning that THIS WILL BE ON THE TEST.
Compared to what crime movies and TV shows like Law & Order portray, very few court cases at the New York County Courthouse end up with someone gunned down on the steps or diving off the roof.
“Listen! I’m not joking! This is my job.”
Or break the knob off making it impossible to turn down.
Although, the damn things do break IRL, and you have to turn the radiator down (or up) with a pair of pliers. In the 1990s, I lived in a $150/month cold-water walk-up, with a radiator (it also had the original gas stove/oven of the world, that I had to light with a match, and looked straight out of a DW Griffith movie-- seriously-- there were no marks indicating temperature in the oven dial). This is how that radiator worked. When I moved in (my senior year of college), the previous tenant explained it to me.
There was an episode of something, maybe Friends, where people were sweltering for days in mid-winter due to a broken knob, and had the windows all open, when one of the friends (or whatever) explains that all you need is pliers to adjust the heat.
Ah, Chekhov’s radiator.
As a school kid I also noticed how, in classrooms in movies or TV shows the teacher taught right up to the bell ringing, as if caught by surprise how quickly the hour went by, and then as mentioned had to yell out the lesson plan as the kids were leaving.
In real life in all classes I had, the teacher had wrapped up whatever they were teaching that day a good 5 minutes before the bell, and all of us students were just watching the minute hand ready to bolt. Nobody got caught by surprise by the bell to leave.
And I seem to remember hearing that bell in movies or TV shows set in universities or colleges, though we never had that bell when I was there.
Something I just noticed, and can’t remember if it’s been mentioned in this thread:
People who have no romantic interest in each other sitting so close they are rubbing shoulders and legs, when there is no space limitation forcing them to be that close. For example, two straight male characters playing video games on a couch, but they’re both on the middle cushion, with shoulders and knees touching.
The show I was recently watching was doing this for thematic purposes. The two friends who just made up were sitting touching to show their renewed closeness, but in the next scene the romantic couple who was going through a rough patch were sitting with a space between them—they’re literally drifting apart.
I’m sure other shows are just doing it to get the shot right, but it does seem unnatural.
I’m not squeamish about touching. If I’m crammed three across in a back seat, or on a small chair lift, and I rub up against some dude, I don’t care, but I would find it very weird if I was alone on a couch, and then even a friend sat so close as to be touching me.
And it seems to me that people on screen often stand much closer to each other when they’re talking face to face than what real live people would do.
Wasn’t one of Doctors Who’s companions a “kiss-o-gram” girl in a sorta constable uniform?
They’d be talking to clouds of dust, asses and elbows. 
Amy Pond when we first see her as an adult — and IIRC as part of the costume she had working handcuffs she actually got to use.
This is like the Social semi circle
Somebody is listening to loud headphones and is completely unable to hear the giant dinosaur/car crash/building collapse/explosion that just happened behind them.
I’ve listened to loud headphones at work while working on heavy machinery, and I can still hear when a machine several yards behind me turns on, let alone something that would produce ground vibrations or air/blast waves I’d feel
The most recent example of this is in the newest Resident Evil movie where a gasoline tanker truck explodes less than 50 feet away from a rookie cop wearing headphones and the cop does not hear it at all.