- The scene in "Radar's Report" where Trapper confronts and contemplates murdering the Chinese prisoner whom he holds responsible for the death of one of his patients. The scariest thing about it is the strong implication Trapper would really have gone through with it were it not for Hawkeye showing up.
- The manner in which Colonel Wortman fanatically describes how General Kelly's death should really be seen by the public eye in "Iron Guts Kelly" can appear really unnerving to some. It doubles when Wortman decides to stage Kelly's suitably-dramatic death by contacting the Navy for offshore bombardment on a sector that was previously mentioned as having no fighting going on, meaning he was willing to shell and kill his own forces to fake the circumstances of Kelly's demise.
- Lieutenant Smith holds the entire medical unit at gunpoint throughout "A Full Rich Day" and never lets up on his threats and intimidation until the sergeant he brought in for treatment is looked after by the doctors.
- In "Mad Dogs and Servicemen", a traumatised Corporal Travis comes out of his shell to Trapper, going on to describe how he and his unit were helplessly mown down by enemy tanks.Travis: Those tanks... they just kept coming and coming. They were so big. They were so big, you know. And... they killed everyone. They killed them even after they were dead. I... I tried. I really tried. But I couldn't move. I... I... I didn't fire my rifle. I didn't throw my grenade. I... I didn't do anything. I just laid there like some coward!
- If you think conditions for the 4077 are tough, especially when the unit endures barrage after barrage of shellfire, then chances are you haven't seen the episode "Aid Station" yet.
- In "It Happened One Night", a patient resting in the post-op ward, Abbott, is morbidly tense, warning the doctors away from him, a clear sign he's on the edge of a breakdown. As shelling starts to hit the camp, the inevitable occurs and Abbott flies into a blind panic. By the time Margaret and Hawkeye get him to calm down, the man is in tears and whimpering, pleading for the explosions to be stopped. He continues to break down for the rest of the episode, snapping at Margaret and yelling at Klinger. Then, as another bout of shelling hits the camp, he panics again, begging miserably for the doctors to let him die before the artillery can kill him. Hawkeye and Margaret's last altercation with him leads to the chief surgeon and head nurse having to physically struggle with him and sedate him. And that's the last we see of him in the episode.
- The episode "Dreams" has a very Twilight Zone-y feel to it. As it includes dream scenes like Margaret in a bloody wedding dress with her wedding bed covered in wounded soldiers, and Hawkeye losing his arms and screaming to the sound of helicopters, or Father Mulcahey's dream where he's Pope and starts to deliver a sermon next to a giant crucifix (shown only from the knees down)... only for dripping blood to splatter on his Bible from the the crucifix, now showing the legs of a soldier.
- Really, the sole purpose of the entire episode seems to have been to invoke various forms of Nightmare Fuel both in universe and out. The only dream that's even remotely happy is Potter's (and even he joins the others in trying to not fall asleep again despite everyone being exhausted) and the other dreams range from implicitly tragic to outright disturbing. The episode is frequently cited as being the most uncomfortable and/or distressing to watch of the entire series to the point where it's not uncommon to hear people say they experienced nightmares themselves after viewing it for the first time.
- The ghosts in "Follies of the Living - Concerns of the Dead".
- The scenes in "Point of View" where Private Rich is choking and struggling to breathe due to his throat injury. Since the episode is shot from his point of view, we don't actually see what the injury looks like, but the sounds alone are terrifying.
- After Charles has been taking amphetamines for too long in "Dr. Winchester and Mr. Hyde," his health takes a downward tumble and he can only answer, "I don't know! I don't know!" when Hawkeye and B.J. ask him what's wrong and not because he's lying about taking the amphetamines, but because he seriously doesn't know what they're doing to him! It's terrifying for those who have experienced or witnessed someone suddenly thrown into the same situation regardless of the cause.
- The situation that Charles and Klinger wind up in in "They Call the Wind Korea," lost, stranded with a handful of injured soldiers, woefully under-equipped for their circumstances, and the strong possibility of any one or all of them dying from exposure during the night. Add the fact that Charles has to perform a few surgical procedures sans anesthesia.
- What happens to Dr. Steve Newsom (Edward Herrmann) in "Heal Thyself". He's showing subtle signs of his true mental state from the beginning and the disclosure that he served at the Pusan perimeter is another clue. The real nightmare fuel is what Pierce and Hunnicutt say at the end: Newsom's fate could be theirs, at any time.
- The first portion of "Life Time" is this and a combination of Nausea Fuel as Hawkeye spends the first several minutes with his unwashed, unprotected hand inside a man's chest to stop some bleeding until Margaret can find the clamp they need.
- Something similar happens a few times when a patient flatlines only for the doctor (usually Hawkeye) to cut open the man's chest and perform an open-heart massage. And it's only the first time it comes up that it's treated as unusual, meaning that they have to do this regularly.
- On a couple of occasions, a patient has started to wake up during surgery.
- In the series finale, the reveal of Hawkeye's Sanity Slippage: during a bus trip where everyone had to be completely silent while the North Koreans were looking for them, a woman couldn't keep a chicken quiet and ended up killing it. Hawkeye's weeping over this seems a bit over the top...but then the camera pans down and reveals the woman was actually forced to kill her baby while tearfully looking him right in the eye, such a horrific sight that Hawkeye suffered a mental break and insisted on remembering it as a chicken.
- "Bless You Hawkeye" is commonly admitted by LGBT+ fans (even if it wasnt meant that way, Hawkeye loved Billy so much that he couldnt even bring himself to admit he hated him) and victims of abuse (Sidneys comment about bedrooms being a battlefield, Billy laughing as he pushes baby Hawk into the water and says youre so clumsy, youd be dead if it werent for me) to be a rough episode to get through. What makes it worse is you can see easy setting up of it in previous episodes with Hawkeye not wanting to talk about a first love in The Bus and his dream in Dreams being helpless on a boat, and his Trauma-Induced Amnesia repeats in Goodbye Farewell And Amen.
Nightmare Fuel / M*A*S*H