How does he know?

We are running this afternoon at 1:30. I am in my pajamas, cleaning house. No running clothes, no running sneakers, nothing. Somehow, Cosmo knows. He is on hyper alert. Any movement I make, he springs into action. If I get out of his sight? Then there is panic. I am in the bathroom. Does he think there is a magic second door and I am going to sneak out and run without him? Make sure your sound is on for the full effect. The voice telling him 'quiet', is the husband's. You can tell how well our dogs are trained by Cosmo's complete and utter disregard! LOL