One of the wonderful things about Horror Films is that the Jerkass will die a gory and satisfying death, usually by machete or eating crow. However, it's not always the obvious things like sex, mockery, or materialism that can do characters in, but... pragmatism?
The thing is, anyone even approaching behaviour that is reasonable and appropriate to continued survival in the Slasher Movie will die. This isn't necessarily because of Wrong Genre Savvy or them being an anti social Crazy Survivalist. Instead, it serves two purposes:
First, it serves as an easy way to bring up and dismiss 'obvious' solutions, often via what amounts to a strawman — it often wouldn't be a very long movie if the pragmatic character calls the authorities, has everyone sit together someplace safe until they arrive, and resolves everything in the first half-hour, would it? So the pragmatic character has to be dealt with, often accompanied by excessive vilification to try and tar their sensible ideas along with them. This is often done by making the pragmatist a selfish, amoral bastard who would leave everyone to die to save their own hide. Never Recycle Your Schemes is applied in spades here, too often the pragmatic character will be shown attempting to do some obvious thing that could ruin the movie (call the cops, leave the area, keep everyone from splitting up, whatever); they'll fail and die gruesomely, and nobody will ever mention the pragmatic solution again.
In essence, the pragmatist must die because he is the most dangerous character in the work (compare The Worf Effect): his mere existence challenges the will of the god of his universe, The Author Himself. If the pragmatist gets free rein, then the author cannot tell the story in the way that he wishes, and so he will eliminate the pragmatist at the earliest possible opportunity.
Second, while leading a group to safety or simply survival, the leader rarely has the chance to be polite, or allow the "niceties" of democracy and universal empathy. Things that, to the fellow characters and the viewer, make them decidedly unpopular. And yes, this is just as big a wall banger as Death by Genre Savviness, as those surviving are Too Dumb to Live (but usually nicer).
Maybe they chose to leave the Zombie Infectee behind because of the risk, had to be authoritative to get things done but was very... "brusque" when going about it, or has outright had to choose to actively sacrifice others for the good of the group.
And they say "Sensitivity Training" is useless.
Compare The World's Expert on Getting Killed, where a supposed expert on a threat is killed by it. The sister trope Death by Genre Savviness occurs for much the same reason, but is based on the character having knowledge of genre conventions rather than just common sense.
As a Death Trope, all Spoilers will be unmarked ahead. Beware.
- In the new Dawn of the Dead (2004), the security guard who wanted to barricade themselves in the mall, rather than letting others in at risk of also letting zombies in, died near the end, after having been "redeemed." Tellingly, he was a Crazy Survivalist who prioritized the survival of himself and the three guards over the other refugees, even making them sleep in a separate and locked store for the trio's protection. Granted, he was a huge dick, but one of them was a latent Zombie Infectee.
- Zig-zagged in Feast. One of the characters decides to save herself and steals the last remaining car, leaving the others stranded to be eaten by the monsters, and manages to survive. However, it returns with a vengeance in parts two and three, where we watch the same character almost make it out of the nearby town (now overrun with monsters), only to take a serious hit to the back of her head and fall, apparently dying. The credits roll while we watch her bleeding out. Then she snaps awake, screaming, and the movie cuts to black. The third movie picks up right there, and she's killed almost immediately by a monster.
- Justified in The Gingerdead Man. The Rich Bitch comes up with the entirely sensible option of leaving the bakery where the homicidal gingerbread man is hiding. Unfortunately, the monster is clever enough to have trapped all the exits, and she is paid for her pragmatism with a knife to the face.
- Debatably the case with Bridget von Hammersmark in Inglourious Basterds after she shoots the unarmed Wilhelm in cold blood. Killing him is clearly the only sensible thing to do to protect the mission, but the audience has reason to like him and it comes across as a bit chilling. She then almost at once makes the murder pointless by leaving behind obvious evidence that incriminates her and leads directly to her own death.
- Classic example in Jurassic Park. Just before the Tyrannosaurus rex breaks out of its paddock, Amoral Attorney and Dirty Coward Gennaro panics at the first sight of the beast and flees into a nearby toilet, leaving Hammond's terrified grandchildren in the car by themselves. The giant predator begins attacking the car and ends up flipping it, trapping them inside, and prompting Grant and Malcolm to try and distract it with flares. The T. rex catches on to Malcolm and begins chasing him towards the toilet where Gennaro is hiding, demolishing the straw structure and knocking Malcolm under the bales, leaving Gennaro to face a particularly well-deserved and humiliating death when the T. rex finds him sitting on the can and devours him. He's the only person who doesn't survive the encounter.
- In Jurassic World, we have the Paddock 11 supervisor, Nick. Although portrayed as a Surveillance Station Slacker and a Fat Idiot, he is the only one of the three men (which includes The Hero) inside the paddock who notices Indominus rex is about to cut them off as they run for the human-sized door. So he goes instead for the big maintenance door which is about to become the sole avenue of escape, managing to be the first person to get free and find somewhere to hide. He unintentionally lets I. rex free in the process, and one of the first things she does is knock aside the truck he's hiding behind and eat him.
- Night of the Living Dead (1968): Tension comes from the argument between charismatic, heroic Ben and cowardly, selfish Harry, about what is the best way to save everyone's lives; Ben wants to barricade the house, whilst Harry wants to take everyone down into the cellar, despite the fact that Ben believes that to be a death trap. Throughout the movie, Harry is portrayed in a cowardly and venal fashion, quite happy to lock people out of the house to save his own skin... and he's also ultimately shown to be right. Ben's plan results in the deaths of pretty much everyone but himself, and Ben himself only survives the night by, wait for it, locking himself in the cellar.
- Piranha 3D had a particularly cold example of this. The pragmatist was determined to get to shore, so he used his motorboat to plow through people being attacked by Piranhas, almost certainly killing some of them. Then his propeller got caught in a girl's hair, and in the process of trying to start it up again, he ripped off her face. It did no good, he was dead in the water, his boat was overturned by people trying to get away from the piranhas, and he was promptly eaten.
- In The Return of the Living Dead, the characters are finally killed because they decide they can't deal with the zombies themselves, and decide to risk prosecution by calling the military. The military nukes the whole town... take that as you will.
- In the Gamebook style Return to House on Haunted Hill, this is one of the possible choices viewers can make, amusingly enough. The pragmatic choice gets everyone slaughtered in seconds. Genre Savvy viewers should know better.
- Stargate: Continuum: Baal meets his end by not being Stupid Evil. While being more pragmatic than the typical Goa'uld gets him great results initially (such as offering the Jaffa freedom), this makes the other Goa'uld in his inner circle suspicious of him. Baal fails to consider that his underlings, being paranoid megalomaniacs like he used to be, will happily backstab him at the drop of a hat, since he expected they would be swayed by the rewards that an alliance with him would offer them. So, as soon as he lets his guard down, Qetesh kills him and usurps his throne.
- In The Thing (1982), Blair is probably one of the very first members of the team to realize just how bad the situation is. This causes him to completely flip his lid. He begins destroying vital equipment such as the radio, then kills all of the base's dogs, then nearly kills several people. Over the course of the film, it becomes clear that these were entirely valid decisions. He destroyed the radio (and possibly sabotaged the vehicles) to prevent a breach of quarantine, killed the dogs as they were the most likely to be infected, and tried to kill the others when they moved to stop him. By the end of the film, he not only dies, but we discover he is now the last and most intelligent of the infected, basically becoming the movie's Big Bad. Though, then again, the time lapse of his assimilation is ambiguous; the alien itself may have been the one to do all these things.
- Violent Night: Morgan Steele, a Dirty Coward wanna-be action film star who is one of the hostages, takes the first opportunity he can to push a few of the hostage-takers out of his way and flee the house with the objective to get to the security team the home's alarm summoned. Unfortunately for him, the security team turns out to have been bought by the hostage-takers and they blow him away as soon as he gets close.
- In War of the Worlds, when Ray Ferrier and his daughter Rachel take refuge in the basement of Harlan Oglivy shortly after Ray's son is seemingly killed in a doomed military operation. Harlan, gone insane after realizing they were surrounded by the aliens, decides to tunnel his way out toward the city, but instantly unsettles Ray due to the noise (Harlan continuously yelling "not my blood!" and that he will be Defiant to the End) and his daughter's safety and kills Harlan.
- Daemon: The Major, and by proxy the entire anti-Daemon movement. Shooting Merritt to Uphold the Masquerade hurts him in numerous ways that lead to the end of pre-Daemon civilization. Obviously it costs him a skilled and determined operative, but not only does it also lead to the Heel Face Turns of first Ross and ultimately Phillips, and martyr Merrit in the eyes of the darknet, but it also pisses off Loki so badly that he vows to kill the Major at any cost. In short, the entire plot of Freedom occurs because he decided preserving the Masquerade was more important than capturing a One-Man Army so deranged even the darknet eventually censures him.
- Jeff in Scott Smith's The Ruins. From the beginning, he is painted as something of a Jerkass due to his cold and calculating nature. In retrospect, this makes him seem like the ideal hero of the situation after the horror kicks in at the second act. Turns out he embodies this trope as well as Decoy Protagonist. He is certainly pragmatic, what with being a medical student and all, and when one of the protagonists (the non-English speaking Woobie of the cast), becomes horribly injured, it is he who suggests an improvised amputation of both that character's legs, in order to prevent infection. Naturally, given their limited resources, his friends reject this idea. He is also the one later on who makes the discovery that this is the least of their worries, namely the Man-Eating Plant covering the hill they are trapped on. After a few more deaths, he additionally suggests cooking and eating the bodies of their fallen friends, in light of the fact they have next to no food or water. The remaining survivors are not thrilled with the idea, and neither is the audience, despite him simply demonstrating the need to survive. One could label Jeff as a Crazy Survivalist, but when you compare him the other heroes, he seems to be the only one with a brain. Naturally, he is not rewarded for it; despite attempting the only logical solution of trying to sneak past their Mayan captors at nightfall. True to the trope, it doesn't work, and he takes 3 fatal arrows for his troubles, as well as being finished off by the sinister vines.
- Father Brown: In "Crackpot of the Empire", Father Brown and a number of others are invited to a Nasty Party in an abandoned mill. When it is revealed what is happening, one of the guests a pompous, bullying autocrat demands that they find a way out and orders everyone to search. When a freight elevator is found, he shoves his way past the others to be the first on board. However, the killer has anticipated his actions and the lift is rigged to crash straight into the basement, killing him.
- The Masters of Horror episode "Dance of the Dead" did this, although the victim's pragmatic decision was unquestionably one of the coldest things on this list. A mother of two sold her older daughter, who was a strung-out junkie in the process of overdosing to a man who would reanimate her lifeless body to dance in his freak show, so that she could support her younger daughter. In the end she was killed and the surviving daughter traded the mother's body for the sister's so that the sister could be buried.
- On Stargate Atlantis, the heroes frequently Shoot the Dog as needed (although it sometimes seems they do it even when a perfectly workable and non-morally compromising solution is available). Doing so also frequently comes back to bite them in the ass a season or so later. Oddly, the otherwise highly Genre Savvy characters don't seem to have picked up on this pattern yet. This turned up in Stargate SG-1 as well, although not as often.
- This basically happens in The X-Files. The Syndicate delayed an alien invasion by half a century, attempted to buy time to resist, and failing that to save at least a small portion of humanity. It was the only rational course of action, but yet they were STILL portrayed as villains. This is, of course, because their Deal with the Devil meant they assassinated people looking into them, experimented on innocents, and generally had their own set of evil plots. Still, they were Well Intentioned Extremists rather than irredeemably evil.
- In Final Fantasy X, a fairly important plot point is the Crusaders setting up a huge trap to lure Sin into a bay and bombard it with forbidden Al-Bhed Machina (in this case, a bunch of cannons and a giant laser). And the outcome of attempting to use an ambush and superior firepower to stop a giant monster? ...Sin's shield is dented, but it recovers and wipes the floor with them.
- In Mortal Kombat 11, Kano has the idea to kill Past!Johnny Cage so that both the older Johnny and his daughter Cassie would cease to exist, effectively taking out three enemies at once. Unfortunately for Kano, Sonya exploits this idea as well and kills the younger Kano and thus the older one as well.
- In the Love, Death & Robots short, "Lucky 13", three dropships land to deploy their ground troops when they're suddenly ambushed by enemy fighters. After the first is destroyed in the initial attack, the pilot of the second tries to take off immediately, leaving their soldiers behind only to get immediately shot down when the fighters make another pass.
- South Park had an episode where the kids all get stuck on a bus teetering over the edge of a cliff. The only reason they don't leave is due to a fear of a monster outside (which the driver made up). The only child (who also happens to be wearing a Red Shirt) that questions the existence of the monster and leaves the bus promptly gets eaten by said monster.
- In The Venture Bros. season 3 episode "The Lepidopterists", a running joke about 21 and 24's seeming invulnerability despite their total lack of competency throughout the series leads up to their concluding that if this were a TV show, they'd be main characters and therefore don't have to worry about being killed. The flipside is that smart and competent Henchman 1, aka Scott Hall, must suffer Death By Samson after his first appearance simply because that's what happens to people who take their jobs seriously in this show.
- Ultimately subverted at the end of season 3 and a ways into season 4 24 dies in the season 3 finale, while season 4 reveals Scott to be very much alive if completely unhinged.