Jesus said "Greater love has no one than this, than to lay down one's life for his friend." John 15:13
The police officer was protecting his fellow friends as well as himself from being attacked, so are you telling me that Jesus would rebuke this man for laying his life on the line to protect others? I don't think so.
Proverbs 12:10 and Exodus 22:4 does not relate to an animal attacking its owner or someone else.