User blog comment:Winchester7314/Possible plot-hole, or maybe a deep hidden reason?/@comment-24.140.27.113-20131013160729/@comment-24.140.27.113-20131013160903

Also to the whole being able to be killed thing it's the same thing about when the souls are killed in Purgatory. They just die instead of having another place to go because again they are just the soul, their human body can't die because it's not theirs and their human body has already died.