Taking a large mentally unstable or highly intoxicated person into custody isn't easy and doesn't look pretty. They also tried very hard not to advance to a more serious use of force. They kept striking green areas with the baton (outer upper thigh) vs escalating the force applied. Probably because they knew more people were coming so there was no need to escalate to a higher force level. We deal with guys high on PCP very often. Pain compliance doesn't work on them because they don't feel it. So "submission" style joint locks have no effect. You can snap an elbow and they don't feel it. So your left with getting as many people as you can and dogpile them until you get them cuffed and hope they don't die from excited delirium or positional asphyxiation. It's not pretty especially when they are naked but its the safest method for all involved.
Very interesting I didn't know that. As I was watching the video, I was wondering why the guy didn't try to take him down and subdue him.
In a case like that though, a good submission hold would be beneficial, no?