This incident that happened in winter caused the British community to be outraged because the police mistreated a man that needed urgent medical attention. They were also angered by selective outrage, people were angry with George Floyd dying in police custody but there was no protests for Henry Novak, no public outcries.
I don't know what happened that night but I noticed that music sometimes makes people more aggressive and dangerous. People listen to a man shouting out threats to a drum beat, that's fine but over a long time it changes them, it makes them primed to fight. The same is true for driving, if people listen to bassy fast music, they drive faster and take more risks on the road. More people wear ear pods in their ear so they listen to music more and they can't hear people talking, they can end up doing something stupid because of that.