What, is it about dogs and their loyalty to their owners? I am not a dog owner, so I can’t speak from personal experience only from what I have seen.
This dog had seen his master go outside for just a moment, and was bereft. Barking, jumping up at the window, pacing about: all were signs that this dog did not want to be separated from his ‘dad’. Finally he settled down, watching and waiting.
Loyalty. We humans have a lesson to learn here.