
Continuity mistake: Lucas returns from getting parts for Optimus Prime, saying he went to the doctor. As he pulls up in his car and parks, his window is up. But then it shows him open his door and climbing out, and suddenly the window is halfway rolled down. (00:33:20)
Chosen answer: The battle that lead the government to hunting all transformers was in Chicago, but the incident that took Optimus out of commission was not. He'd been on the run for however long, even changing his appearance to avoid detection, when he was ambushed. Wounded, he snuck into the theater to hide before transforming one last time into vehicle form at which point he basically passed out, lost consciousness, or whatever it is robots call it when they involuntarily shut down (stasis). His aggressive reaction upon waking is simply down to his instinctive warrior reflexes immediately kicking in. All humans are a potential threat to him now, so he reacted accordingly in an instant.
Phixius ★