I had a school teacher who was a Marine in the Korean War. You may have seen his picture. He can be seen crouching around the corner while a buddy is shooting at a sniper in Seoul after the Inchon landings.
He told stories in class about his experiences. One was how he watched U.S. and Chinese (Russian ?) jet fighters dueling high above the Yalu River. He said that is how he overcame his own PTSD, before PTSD became a thing.
I’ve seen that picture a number of times. What an honor to be a student of that Marine.
What’s interesting about that photo is I believe the Marine firing his carbine is holding it to his left shoulder instead of the right shoulder.