To me it seems like the guy was just turning his hand and he accidentaly hit the woman which he didn't even know was there. I don't know if that was the right thing to do there by the boxer, but who knows what they were saying i didn't understand a word.
Seems to me the guy saw the guy and girl coming, he seems to look their way, then throws his arm out. Reckon he wanted a fight or to cause some trouble with people he didn't think would fight back.
To me it seems like the guy was just turning his hand and he accidentaly hit the woman which he didn't even know was there. I don't know if that was the right thing to do there by the boxer, but who knows what they were saying i didn't understand a word.