Thanks, porkchop!
So, the officer could have been videoing on a phone.
But, the phone may not have been his hands as he was videoing the scene and simultaneously shooting his gun because the phone could have been firmly attached to the front of his vest - similar to a vest cam.
That info and the visual help to clear up my confusion!
I’ll have to check, but I think the other video, the one the left used to try to insinuate that she was NOT trying to kill him, shows him using both hands to draw his gun. So that phone holder thing would be ideal for this situation.