Glad that you noticed that
Perhaps you may also have noticed another evident element: his punches were not hurtful. So, you could afford close quarters, and since he was inclined to uppercuts (well, the other guy kept his head lowered and could see his arms instead than looking at him in right the face, so he was inviting
uppercuts...), find marvelous ways to his chin tip by hooks
- for with uppercuts his face sides are exposed to hook routes.
However, another thing immediately obvious - you could not count on making him run out of breath any soon... this is suggested not by the fact he is so forceful (guys who start fast may end fast, actually) but by the fact he is while keeping physical composure
(the guys who was beaten instead was very unorderly).
That (composure) spells for some factual experience.
At the end of the video the "cop" fires a good straight right - too bad we cannot see more to guess how he could behave or find himself comfortable with distance fighting.
All small things that you can process just within the first 10 seconds.
However, a person who is not used to fist fighting (and that was a regular street fist-fighitng, for which MMA or boxing experience makes the difference) would not last 2 minutes with that secuity guard. Less than one round and then it's over.
While I agree that street fights often look like that among the less dangerous portions of the population, the fact is that most people can't fight their way out of a wet paper bag. They just get drunk and angry.
Most of what the guard did missed. He even misses the initial counter. His virtue, such as it was, was that he was throwing out enough that the other guy wasn't really giving him anything in return. But he wasn't keeping it together. He'd just got into a position where he had to keep swinging to stop the other guy making any decisions. If was experienced he'd have picked his shots with a purpose that set him up to actually deliver stuff, rather than just throwing it out and praying for a hit.
Most of what I saw wasn't suited for the range at which he was attempting to employ it. He didn't either didn't appreciate or hadn't trained the reflexes to adapt the tactical role of his movements. That suggests to me, rather than fist fighting experience where he'd have run across that problem before, he had some gym training - boxing perhaps - and bad training at that.
Could he beat up some random numpty who'd never thrown a punch in their life? Sure. Could he have taken your average drunkard? Sure. But anyone who'd got a couple of week's worth of paired reaction drills and some light-contact full-speed fooling around to their name would, I suspect, have had him for breakfast - even a beginner with no experience actually fighting. They wouldn't have had to work out what his game was, they wouldn't have found themselves being forced into a certain pattern of response that set them up on the losing side. He didn't have a game - he'd managed to adequately paralyse his decision making process without anyone else doing anything other than standing in front of him.