The 4 million dollars is meant to be punitive, not proportionate. It actually makes a good deal of sense as a legal principle. (Disclaimer: not a lawyer, just have an interest in this stuff. Ask me about the famous McDonalds hot coffee lady sometime!)
Let's say you get injured while riding a rollercoaster, and the amusement park is definitely liable. You have $15 000 in medical bills, $20 000 in lost wages due to medical treatment and convalescence, and you expect to spend $5000 on the lawsuit. So you sue for $40 000, right?
Okay, fine--but the amusement park is earning more than a million a week in profit. Your $40 000 award will barely make a dent in that $50 000 000+ annual take. When courts award punitive damages, they're saying that the defendant needs to feel the full force and impact of the lawsuit: the judgment isn't meant to be a slap on the wrist, it's meant to be a serious charge of major wrongdoing which must not ignored. Beefing up the award has been a good way of sending that message. We might also consider that, in these situations, it is likely that other people were also exposed to potential injury: you just had the misfortune of being the one actually injured. In this case, the problem isn't the injury itself: the problem is the carelessness on the part of the defendant which led to your injury, and may have led to others. As such, those potential injuries get rolled into your lawsuit, since identifying every potential victim and including them in the mix would be an onerous and in many cases impossible process.
That's where you get 4 million in damages base on $40 000 in actual injuries. It's about sending a message, not necessarily about the actual damages.