Reloder 28,
A TSX that loses its petals doesn't have a pencil-point, so hardly pencils through--partly because the petals don't necessarily fall of on impact. As my post noted, one of the petals was found a couple inches from the bullet--which was found under the hide on the far side of the elk.
I have seen a few bullets "pencil through" animals over the decades, and believe me, the minimal damage they do isn't anything like what occurred to this elk's lungs.