First, what "could" have happened to your son is not relevant: the law only deals in what did happen, not what might have.Second, when talking about a possible design flaw, your opinion, as a layperson, as to whether something is badly designed is also not relevant: you lack the training, education, and experience to offer an informed opinion. Only if an automotive engineer or safety expert thought the design was dangerous might you have a case.Third, you can only sue for actual medical costs and injuries. If, as we hope, you are not badly hurt, then even if the trunk was badly designed, there would be no point in suing: a product liability suit like this can be very expensive, due to the necessity of hiring an expert to examine the car, write a report, and testify, so if you are not badly hurt, with injuries disabling you for months or longer and/or very large medical bills, you could spend more on the lawsuit than you would ever get back.