I've been fairly critical of protestors before, but in this instance, you can see the police going in for a fight, already heavily outnumbered. I'm not sure what they expected to happen, but the officer drew his gun almost instantly and shot a high school kid at point blank range.
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.