Police know that suspects frequently try to avoid arrest by lying. They do not trust the suspect, hence the knee on the neck to control the uncooperative suspect. A gymnast will tell you that where the head goes, the body goes. Also if the blood to the brain is cut off he would’ve passed out within 10 to 20 seconds, not eight minutes. Watch this video of a rear naked choke by an MMA fighter
https://nypost.com/2019/04/09/ufc-champ-jon-jones-chokes-out-fan-and-it-gets-briefly-terrifying/