In the real world, I have converted a sedan into a convertible, quite easily, using bullets. Not even a lot of bullets either. If the other guy is firing anything with greater hitting power than, say, a .32 (Google .32 caliber, .45 caliber, 5.56mm and 7.62mm...I can't do it ALL for you) it will go through things. Metals, woods, sheet-rock? No problem. Your front door will not protect you, at all. Nor will the walls of a normal suburban house, nor the three Sheet-rock walls beyond that. In a car, the only thing that really stops most bullets would be the engine block itself. All the rest of the body of a car, well, basically tin-foil. All those cop movies you remember from the 70s, when they hid behind the opened door of their patrol car and shot at the bad guy? Yea, no. Do not think that works. That is stupid, and nobody but actors in Hollywood actually does that.