Yes, we do know the timeframe from the stories provided. He had lots of time to get in his truck if he's telling the truth. 4-5 barks=10+ seconds.

I like your fantasy about a family's loyal labrador becoming a vicious killing machine in the space of a few seconds, about to rip off the face of a child, heroically dispatched by a Hollywood producer who generously moved to Alaska to become a co pilot for a regional airline and who was so afraid of the animal in question that he parked his vehicle in its yard and walked his toddler over to it.  A man so responsible that he keeps guns in the house with four toddlers and apparently posts nude pictures of the kids on social media. yes this man is certainly a worthy subject for our admiration.

For the rest of us who have survived decades on earth without having to carry guns around to protect us from the shadows we jump at, the mentality required to feel that you need a concealed weapon on a day to day basis is really incomprehensible.