It seems feasible to me, because I know, for my own safety, I wouldn't take cover behind a car door. I've seen and read from too many sources that it's not safe.
There's a website, though, called The Box O' Truth, that does a lot of testing. One of their features is called
The Buick O' Truth, and, according to their tests, it's unlikely for a pistol to penetrate both doors.
I would consider the circumstances--and the dramatic implications. Was she taking cover behind the doors, providing an opportunity for another character to comment that she shouldn't have done that? Maybe to comment that life and death all comes down to chance, comparing the car and bullet to a pachinko machine? Was she caught off guard, or did she choose to take cover there? If she chose to take cover there, why didn't they aim for the legs?
Even if it is bad cover, a car is fairly good concealment. So, it would be unusual to get shot in the chest through one.
For the bullet to pass through both doors and her side, she would have to have been squatting behind it. With her side facing the assailant, also.
I read in at least two ninja training books that a puncture to the lung will prevent someone from screaming. One advised stabbing someone in the armpit for silent killing. I think the other one was discussing crossbows. LOL I don't put much faith in them, but it makes me wonder if she would be able to talk.
I know fighters sometimes get a
punctured lung and come out of it fine, so I don't think lung penetration necessarily means death.
A gunshot wound to the heart, as far as I know, almost always kills. I found an
article about it to double-check.
I also found this
book excerpt about deer hunting that might help.
The injuries to the lungs and heart, I think, would depend on if they were caused by bullet fragments or an intact bullet; also on if the round bounced around inside the ribcage.
I remember a Discovery Channel show from at least ten years ago in which an EMT or emergency room doctor compared the human body to a water balloon; you can throw it off a roof and stomp on it and be amazed that it didn't pop, but sometimes a tiny pinprick will cause it to burst and collapse.
Then there are stories about officers shooting a man in the heart, who keeps running for 90 seconds.
I think, because the technical details of the injury would be minimal, the reader would fill those in based on the time of death. If she dies instantly, they must figure she'd had massive blood loss from the heart. If she can't speak when help arrives, because of the collapsed lung, and then she dies of a heart attack after surgery, they'd figure she must have had a bullet fragment lodged in her heart.
I'd decide how long it takes her to die based on the dramatic needs of the story. If you don't want any kind of moment between her and another character after she's shot, she should die right away. (Unless you want someone to comment later about how she died in agony all alone.)
Or: Her body might slump over, causing her head to impact the curb, knocking her out instantly. Then she dies some time later, without ever waking up.
For me, I have to see it in my mind. Whether it's 100% true or not isn't as important as whether I can make it plausible for myself. So these comments might help. I'd love to have a table, though, that lists average times for various injuries.