OK, just to get it clear in my head - would you consider a pet a loved one?
I'll play my cards to be fair here. I don't actually know what I'd do in the case of one of my dogs. I would attack anyone who would harm my family, and probably my dogs. I would try and keep from killing them as long as I could insure the safety of the aforementioned. I also think I would do something similar if I saw someone else being attacked.
Now, with that said, I'm well aware that I cannot guarantee what I would do until I'm faced with that situation.
Yes... my pets are like a family member to a certain extent. When guests arrive, they are usually put outside or in another room, unless the people are adults and don't mind. Children/babies.... that's a whole different thing. Pets go out or in another room period.
And I wouldn't know what I'd do until faced with said situation either.