The photos suggest a below the knee amputation, but they never show how far below.
Unless the auger screw took care of the tibia and fibula and all he had to cut was mangled flesh or unless he had a Swiss Army type knife with a saw blade, I'm a little skeptical.
He also had the poplitial and/or tibial and lesser arteries to deal with. They would have initially retracted in response to the trauma, but not for long. I'd be interested to know how much blood loss occurred.
This response is an indication of why Sarah will not watch medical dramas with me in the room.