She then asked again to which I for some reason felt I needed to respond, asking her "how could that be your business?" She then said "fine, I'll call them." I didn't know if she was wanting to call the police on me or what, so I left. Did she think the police were going to catch the person, and then they could have their auto insurance pay for a bunch of treatments I wasn't going to get?
I'll give you a hint, DUmmie: She more than likely correctly guessed that you were the one at fault in the hit-and-run, which is why you left when she said she was going to report it to the police.
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I also have a hunch that she smelled booze on your breath. I have no proof, just a gut feeling.