CA laws regarding self defense shooting from inside a car?

Not sure man, good question. I'm a business owner and my facility has two parking lots. I was outside playing with my dog and was wondering the legality of CC'n in my own lot. Unfortunately it seems like as long as my lot is accessible to the public then I'm SOL. My idea was I can walk to my car in my own lot with my firearm concealed to feel safe to get to my car. Once inside my car I would put my firearm in a lock box. From what I've gathered that's a no go. I spoke with one of our friendly neighborhood deputies and he told me not to even bother getting a ccw or using a firearm because I'd get in trouble if I step outside my door with it. IDK fuck this shit.

/r/CAguns Thread