I don't disagree with the rest of your post, but I think this one remark is laughable. Did you even watch the video? Now keep in mind, this was in a dense residential neighborhood, with his partner downrange from him. Notice his apparent aim as seen from his bodycam footage.
I mean, the officer not only believed there was gunfire (from the handcuffed guy in the back of the squad that had already been searched), but believed or at least claimed that he had been hit. He wasn't trying to spook anyone, he was the spooked one and way too scared to be a police officer.
He's a high functioning individual. Has a bachelor's. He has combat training. His role had him in combat areas but he wasn't expected to be on the front lines kicking in doors and other grunt work.
All of his credentials indicates that he knows how to read training manuals and understand the rules. Then after studying said rules and protocol, he can put them into practice in high pressure situations.
I doubt he has severe PTSD based on his particular place in the hierarchy. He might have saw some action, but he wasn't the real door kicker or peacetime janitor enlisted infantry are. He also wasn't allowed to fraternize with his lower enlisted soldiers(it's actually a crime); meaning he wasn't allowed to get close to them mentally.
He was at risk for his life during his service, don't get me wrong, but it was still lower than those under his command because they protect officers while the enlisted grunts are the meat put out in front.
This is not to say he doesn't have self-control and experience with combat training. The guy passed Ranger School as a requirement of becoming an infantry officer. He brought his Army BS with him and decided to give the civilian a scare. After the rear window got cracked, he could have easily gotten off a good shot. It very well could be that he did want to cause an "accidental" kill, but he didn't want to be the one who fired the killing shot because the guy was cuffed. Rather, he created a scene which would induce the partner cop to potentially kill the suspect. Because unlike him, she could have the excuse that he misled her into believing shots were fired. His misses were intentional. With his past training, if he wanted to hit the guy in the head, he'd easily get his shot on target.
There is another layer of leadership in the military. Warrant officers are the actual "technical experts" that also lead the infantry. They are also enlisted non-commissioned officers, and subordinate to the commissioned officers. There are many "leaders" in the military so that if one goes down, another can continue operations.
The Ranger Handbook is not a short read; it's about 300+ pages and he studied all of it in the past.