"I know I had no debris on the keyboard or screen"
I'm sorry but everyone saying something along these lines are absolutely high. You don't know this. The screen didn't dent itself. The pixels didn't explode. The glass isn't defective. You had some s**t on your keyboard. It was a crumb, a flake of skin that dried, something, that was on top of the keys or the trackpad or the palm rest. You closed the screen. That s**t impacted at the right angle and with the right force to cause the damage. The other 50 times it happens, you didn't notice it, it didn't do anything. The 1 time, it did do something. The tolerance between the screen and the deck is insanely small. You didn't mean to do it, but it happened. Don't get defensive about it, this s**t happens everywhere. To laptops, phones, cars, etc. But the idea that these things are a defect that "just happens" when they are impact- or corrosion-based is some wild thinking.