Oh Jack, don't you know that you have to pay attention in a fight to the death? Because that's what this is — if we're reliving memories we're doing it to the fullest and he's not holding back for once, instead focusing all his attention on dodging the sword so he can pummel Jack to the ground. It's all fangs and feral aggression, brought with pinpoint ferocity.
After all, he is a killer. Killing is what he does.