But up to that point of "The Kneeling" as we could call it, he had not been so nice about the arrest procedure. So why would they think he would now be more cooperative? By their experience they have probably found that most do not become more cooperative especially if they suspect the individual is on drugs or something that is influencing their mind.
Welp...Through the training they received through their department, they should have known that after 3-4 minutes of kneeling on the neck, the guy is so O2 deprived that he would not have the strength to resist. And yeah, I hear the kneeling on the neck technique was taught. At some point, a person with any sense would know that kneeling on a major vein supplying blood to the brain, thus killing bloodflow, will have an effect after a time!
Ever hear of a sleeper hold? They work by employing the same principle. They don't take 8 minutes though. Hmm