Gray area is proudly the wrong words.
Lets say a bad guy just shot someone dead and runs away. No one is going to think twice about a police office shooting the bad guy in order to stop him/her from getting away. No jury is going to convect them on it. CHL holders on the other hand can't by law shoot anyone running away.
Sorry. You've been watching too many movies. No police officer is going to get a "Get Out of Jail Free" card when they just up and shoot someone (even if said someone just committed murder) for the
purpose of keeping them from getting away. Not no way, not no how. Running away poses ZERO THREAT, both to the officer and the public. And zero threat does not allow lethal force.