It is a total power trip. He sounds a lot like Ted Bundy. Remember that Bundy would hate it if his victims started talking and ruined his experience of their murder? If Terri had begun to miraculously speak and beg for help, he would have yelled at her to shut up so she wouldn't ruin HIS experience of her death. Sorry to be macabre but that was the analogy I saw.
May G-d bless Terri's loved ones and may G-d please help the United States of America.