I think it would be a crime to save a pet over a human being. Human beings use reason (the most of the times) and can use their intelligence to improve our world. Animals just cannot do that. We need every single mind in order to make our world a better place, and the destruction of a human mind is (for me) a catastrophe. With regards to animals, they only live to reproduce themselves, so they can be left to die as long as their number is not largely affected.