Chuck: Stahl made the club think that Opie was a traitor and giving the FBI info on the club. The club put a hit on Opie and accidentally killed his wife instead (Tigg was the shooter). Opie found out and knew that Stahl was behind the deception. He even confronted Stahl once before about it. That's why she was so scared. She knew how much he blamed her for Donna's death.