Toward the end of Sunday’s The Walking Dead, we kinda saw it coming. But Siddiq? Not so much, even though the Michael Cudlitz-directed “Open Your Eyes” followed the show’s tried-and-true pattern of killing off characters: Suddenly play them more heavily than ever before, attempt at the last second to get us extra-invested in them, then… bam. How did the last friend Carl ever made go to his grave? Read on and find out.