It's a constant back and forth, the protestors take the upper hand and then it's the police. In this video a police officer singles out a protestor on the ground and begins to beat him as a group pf his fellow protestors come to his aid. And after the protestors begin beating the police officer her resorts to the only thing he has left, his gun. 

footage of a police officer trying to beat one protestor, got beaten back by the protestors but pulls out a gun to protect himself at the International Airport in #HongKong. pic.twitter.com/eUW5mGfo5s

— Aviationdaily(@Aviationdailyy) August 14, 2019