After watching this several more times and stop/starting it at the first shot, it looks pretty clear to me that the first arrow went right through the bears stomach. You can clearly see the bear hump up as the arrow hits it. Why it didn't go apeshit is beyond me. You can only catch it when you slow it down. That would make sense looking at the hole in its gut (exit side) when it is laying there. The second shot looks like it might have hit something hard as others have suggested and was broken off. You can see the lumenok fall away as the shaft is snapped. Anybody see this?
