What decision does Hank come to about Penderson in Chapter Three? Why?

Hank decides that they will make Penderson's death look like an accident by running his snowmobile off the bridge into the frozen creek below. Hank sends Jacob down the road with the car, telling him to wait a few minutes and then return to pick up Hank. After Jacob is gone, Hank discovers that Penderson is alive and hesitates only a moment before smothering the man with his scarf.