Sure they have. Crocodiles are cold-blooded; they are known to be able to estivate for months without food, waiting for better conditions. Birds and contemporary mammals are small; they can hide, and survive on small scraps. Dinosaurs were both big and warm blooded; the resulting metabolic demand is fatal in hard times.
Not saying the authors aren't right about being able to find shelter against heat pulse also being a factor, of course. But it's not the only explanation.
This is what always bugged me about the impact extinction scenarios. If it really had that devastating an impact on the entire planet, then why only the dinosaurs and not all land vertebrates?
Does that mean that none of the dinosaurs would have been sufficiently sheltered and capable of surviving the aftermath, but birds, mammals and amphibians could?
Mammals didn't survive as such. The big ones died, as did many, many other species. As the paper points out, "mammals surviving the K-T event were generally rat-sized or smaller".
Generally, there are more small animals than big, I mean more individuals of a particular species. There are more flies than elephants. If the chance of of an individual dying in the Big Oven is 99%, greater numbers help the species survive.