Nothing worse than an untrained bouncer. If he knew how to take down someone, he would also know how to do it with control. There are so many things that can be done in such situations, taken from Judo, wrestling and Aikido.
Instead he wastes time on this one patron, having trouble subduing a man smaller than him, until he eventually gets lucky and unloads his rage by breaking his skull on the pavement.
This "bouncer" should be put in prison. He's not fit to be in the civilian environment.
Try that shit with a Cop sometime, see if they're going to wrestle around with you.