Your shot hit right in the "knuckle" where the humerus meets the shoulder. This tough bone joint likely started the massive expansion prior to it entering the chest cavity plus blew bone hunks in there too. The bullet may even have started opening prior to hitting the deer if it hit any of those saplings in front of the deer.
I shot a doe with a Nosler partition once that hit a small grapevine right in front of the deer. The entrance hole looked like a grenade went off since the vine started the expansion early.
You are seeing the video from about six foot underneath me. I had a wide open lane to the deer's front shoulder with no obstruction. Usually when bullets hit saplings or vines it makes the bullet tumble and inhibits expansion of the Barnes as it would go in sideways. That's neither here nor there. Bone or not, the Barnes are without question the meanest bullet I've ever shot. If you've never hunted with them, you are doing yourself a disservice.