Would love to see the forensics diagram of how someone in the back seat can be hit by a ricochet in the back of the head.
Read the story. The person in the back seat shot the person in the front seat in the head. No ricochet involved.
The person in the back seat fired the gun. The woman in the front passenger seat was hit. The bullet apparently hit the "seat rest" first, which would have a metal frame, and then hit the woman in the head.
The energy lost in hitting the "seat rest" may possibly have saved her life.
My car seats have arm rests and head rests. I don't really know what they are calling a "seat rest".