He walks through the scale of the KT impact: a six-mile asteroid that wiped out three-quarters of all species on Earth and likely triggered every fault line on the planet. Then he poses the question that puts it all in perspective. What happens when you triple that size? The answer is straightforward and sobering. We wouldn't survive. This isn't speculation or fear mongering, it's basic physics applied to planetary catastrophe. The energy released scales exponentially with mass, and the cascading failures across geological and biological systems would be total. He's not trying to alarm anyone, he's illustrating the threshold beyond which recovery isn't an option.