Apparently not high as a kite. Local news watching the protest, made the point, they didn't even ask him to get out of the car, simply reaching in and dragging out by the collar. The cops were wrong from the word go, at least by their own body cams.
I don't know what that other tool might be. What we need is better training and discipline in the ranks of blue. Memphis is 500 cops short. Of these 5, none over 3 years on the force, and I heard, average age 24. 24 not being the most self controlled age of young men, and they are hired younger than that. Thorough comprehensive training is a must and part of that must include emphasis on not only self-discipline by procedure, but also the absolute duty to step in and stop fellow officers when out of hand, and of course continued close supervision with more senior people on the street, taking a tough view, not only of crime and criminals (and in this case how minor traffic violation stops are handled) but a tough view on the operations, discipline and adherence to Standard Operational Procedures and department policy. The lack of restraint and the brutality was simply horrendous.