Not much to say about this story, other than a good deed had a good outcome. (So Far.) My advice is to not intervene; however, a life was saved. The good guy (a convicted felon) probably has few assets worth going after, so he is probably safe from civil action by the family of the decedent. Read story here: Felon saves Trooper's life!
This is not always the case. Here is another example of a citizen saving a police officer's life and being sued by the family of the decedent.
Your life will be altered forever. Make sure it's worth it to you and your family.