There's been other instances today where police was just looking to fight protestors, and as soon as they realized protestors weren't having any of it, they drew their guns and shot in the air. There's a difference between an officers' life being in danger, and the officer stupidly putting his life in danger.
And protestors obviously looking to fight police. They swarmed the other officers partner who was being beaten on the ground and he was next.
I find it shocking so many people were expecting him to just take it the beating or 'run away' and leave his partner there.
There's a very good argument for having police on the streets when there's protestors running around throwing petrol bombs and swinging metal pipes. This is basic civil society 101 stuff. I'm not convinced the solution to China's totalitarianism is random street violence and property destruction by teenagers.
That's what the protesters are expected to do.
Attacking the police was definitely a bad idea, especially for strategic reasons--this illustrates why Ghandi and King preached 100% passive resistance. Protesters can allow themselves to be brutalized for months, and the moment a few of them hit back, the narrative starts to shift to "violent thugs."
If you want to retain the moral high ground in the face of organized propaganda, you're not allowed to physically defend yourself even once.