Well, it was 1 hour, forty minutes and thirty-three seconds.
"only those organisms already sheltered in burrows or in water were left alive"
What about Mosasaurs and Ichthyosaurs?
I'm not a scientist. but I did just finish a museum exhibit on paleontology a few months ago. I would assume that such large animals would have been faced with a new environment in which they had to adapt or die. They either went extinct, or adapted to meet the post extinction event, and evolved into other species.
You make a good point. All sorts of species and genera died out with the Cretaceous-Tertiary extinction. Most people only focus on the larger animals, while ignoring the plant kingdom. But there was another natural kingdom to consider - the microfauna. I spent quite a bit of time in my career working with micropaloentological data. These data often provide a better, more complete record of climatological change than do terrestrial fossils. I do not believe the micropaleo records supports a "sudden" extinction.
High metabolisms. Needed to breathe frequently, therefore needed to surface, therefore needed to transit the boiling hot surface to get to the air, and were unable to shelter in deeper water.
Tunnel dwellers are accustomed to lower oxygen and higher carbon dioxide in poorly ventilated burrows...