Erica paid for goods she bought at the electronic checkout by the exit turnstile of the supermarket. Just after she paid for the goods, Cam, the floor supervisor, took over the exit and, mistakenly believing that Erica had not paid, refused to allow her to leave with the groceries unless she paid for them again. Erica refused, so Cam asked her to accompany him to the office to discuss the matter further. When Erica refused, Cam took her by the arm and started to pull her towards the office. Erica responded by first telling Cam to stop, and then when he didn't she hit him in the face with her grocery bag, knocking him unconscious. Discuss.