I understand you think the Police officer was wrong. But looking at the whole scenario.
You're a firearms cops going to arrest someone in an airport. You are met by extreme violence, you manage to Taser one of them and then are attacked from behind in a chokehold. You have a gun on you.
You get up and see the bloke appear to lift up from the floor. It's a confusing chaotic situation. I can understand why he's kicked him thinking "You are not in any circumstances getting to your feet".
You also have other injured cops, and cops with firearms who had/were being assaulted.
Let's face it, they were lucky they weren't shot, fighting with cops with firearms like that.