I agree to a point, OH.....but the reason I cite the setup (and shot distance)is....if you WERE to be off a little "forward" (forward for THIS shot). That could be a glancing blow to the ribcage.

Where THAT arrow entered (and the one I showed).....there's nothing but skin to penetrate ("back" of the ribcage).....and soft tissue, inside. I said right away, like you, that this shot is 100% lethal. I stick by that.