Situational awareness is paramount for everyone and especially for police officers dealing with situations where there is an obviously hostile crowd. Don't get so absorbed in the task at hand that you forget about what's going on around you. I'm not posting this to be critical of the officer's actions but as a reminder to be ever vigilant concerning your surroundings.
http://www.youtube.com/watch?v=KgCz3...layer_embedded
Personally, I think he should've kicked him harder.