Beware of dog part 2

For the second time this week Regis sensed or heard something we didn't and ran to the front door barking - only this time it was 4:07 a.m. and we were fast asleep. I got up (had to pee anyway and B didn't want to get out of bed) checked the door and kept watch at the crack beneath the door to see if I could spot any shadows and feet lurking around. Regis kept eyeing the door though no one was outside to my knowledge. After he calmed down I went to the bathroom and returned to find Regis gone. I looked in his bed and around the living room only to find his lying at the foot of our bed. Was he there to protect us or for us to protect him?

Does Regis hear or sense someone that we don't? Or is Regis turning into a sleepwalker and living some subconscious super-hero dog dream? Will I wake up to find half-eaten ice cream containers and empty milk cartons lying by his bed next?