They always cut the video just after he hit the ground. But he obviously is awake for a while afterwards if you watch the whole thing. So the headlock was not the cause. They should have taken more care in determining if he was having a medical or breathing issue. He was telling them he couldn’t breathe.
he starts the headlock at 38 seconds into the video, it’s released at 53 seconds. That’s a total of 15 seconds.
https://www.youtube.com/watch?v=j1ka4oKu1jo
The video continues on for a LONG time afterwards.