My experience has been to see really well trained people react very calmly during conflict but then, even the most experienced, often feel a bit sick or overwhelmed once the situation is over. Must be the coming down from all of the adrenaline.
In my few times when I actually felt I was in the middle of something ... serious, it sort of felt exactly like that. There were lots of fights broken up, drunken brawls being separated, people being escorted out when they didn't want to go, etc. Not serious, but to be taken seriously, if you understand what I'm saying here. I'd guess the LEO community, military, private security people would get it. Situations arise, and on their face they all have the "potential" to go ugly, but they typically don't, just keep your head and things will be fine.
And then there are those other times.
Once I needed to break up a fight between two older guys in my nightclub. Our crowd was a mix of local folks and the college crowd, all mixed up in a fun mix of 20's to 30's folks, all out to get their drink on, dance around, play some grab-a$$ etc.
So, one guy in his late 40's came in with this very hot also 40's lady, and I assumed they wree married and out for a good time with the young folk. Not so. His ploy was to take his buddy's wife to a place where his buddy would not find them (I found out later that they'd been having an affair behind the husband's back for about a year or so). And... like seems to happen all the time on Lifetime, the husband found out about it and was watchful, and told his wife a story about going out of town. I learned all of this later when everyone was talking tot he cops.
Husband comes in, pays his cover, and heads to the bar. He gets tot he bar and spots his wife and his buddy (probably not any more by then) sitting in a booth (bad tactical position, eh?) and he just waits for a bit (this is pieced together amongst the security guys later). Both guys are also (also found this out later) ex-military. Husband sees buddy playing kissy-face and boob-grabbing in the booth and does not see the husband get up from the bar and head over (this last bit from one of our waitresses). Both guys are in good shape, neither guy has had much at all int he way of alcohol yet, and things go from steamy to Nova-hot and combative in the blink of an eye.
And of course, that blink is when yours truly walks around the corner, right as husband (another tactical issue here, but emotionally driven so maybe I get it) walks up, leans over the table and grabs his wife's arm (she's still tongue-deep in Buddy's tonslils, remember) and attempts to drag her out of the booth right over the buddy. Buddy takes offense, and it's On. They hit the ground and I'm right there with my favorite thing (not any more for obvious reasons), and I step on one guy's hand while jamming the other one's head down on the floor (great tactical sense myself on display. Not.) I may have shouted for back-up. I hope I did, no clue. My problem is, I had left somone out of the picture... remember the girl/wife? Well, she decides to kick at me, and automatically I slipped that, and palmed her fce and put her back in the booth -- therefore enciting both guys even more at me. I don't think I've ever seen two guys get off the ground that fast. I'm very positive that my 21 year old self's eyeballs were a bit... ahh... large at that point. It was OK for them to get in a fight, sure. But for me to try to fight with them, or break it up, or put my hands on his... uh... their woman? Nope. I remember doing a nifty two-step around a table and thought I had gained a moment of contemplation, until the husband reached out with one hand and threw it out of the way.
And then the cavalry arrived in the form of my other 3 compadres and an off-duty officer we all kept in the loop.
I think I'd have been ground into Malt-O-Meal if they'd not arrived and it wouldn't have taken those two long, either.
Thing was, I felt pretty calm while it was actually happening, with thoughts like "Really? Dragging her out through the guy? That won't work." and "Pretty lady." and "Low-cut top." and "Huh, boots on both." and "What's with the eagle tattoo?" and "Wow, that was fast." and "OK, now I can... oops, maybe not." and concluding with "Whew."
And, about 45 seconds later I had to sit down. Hands shaking, legs not wanting to hold me up, feeling like supper was going to come back up. Ug. And then having to talk to the cops about my "assault" on the lady. Good thing the waitress I mentioned above saw her try to kick me.
Anyway, sorry about short story made long. No knives in the story, either. Well, that actually came out anyway.