It was ONE bite and it severed a major artery.
It’s like when my mother’s 7 pound cat killed a large doberman; the cat got in a lucky bite to a major artery and the dog bled out in seconds. If the dog had bitten first it would have been all over.
Had a neighbor once where this type of thing happened to her husband. He was hunting, set his rifle down against a fence to climb over it. His dog knocked the rifle over, it discharged, caught him in the femoral artery. Bled out in no time. Really sad.