Brock, that arrow looks exactly like mine last year. Pass through shot with the same amount of blood. Only difference is mine bled like crazy for 400 yards or so. When the guy shot him on the neighboring property Monday of gun week, he said one lung was deflated and my shot was high. The buck I hit lived for 2 1/2 weeks on one lung.
Id say there's a good chance his arrow travelled through no man's land, like mine did, and got wiped clean. Probably the only difference in the shots was mine punctured the front lung and exited low because of the steep angle down, thus leaving a good blood trail. Mason's may have hit just above the lungs and went straight through since he was ground hunting.
Either way, it sucks, but as Aaron said, we've all been there.