The female patient is trapped under a tow truck. Her leg is trapped between a grass lawn and the body of the truck. None of the doctors or medics present thought to trench under the leg to free it vs amputating it.
Dr. Kinney and Dr. Goran both refer to the tool used to do the amputation as being bolt cutters. The tool was a lopper used to prune tree limbs. Bolt cutters have a very narrow opening and would not have the range needed to cut a leg bone. While a lopper would have the range, it would be unable to cut through bone as they are used on soft woods.