alan wagner

Attending some AZ Fall League games this week I saw the following scenario, at least twice: Runner on first, ball hit into the alley, likely double. The second base umpire ran to the outfield to watch the play, the third base umpire ran to cover second, and the home plate umpire covered third. The first base umpire never left his post. Should he not have gone to cover home should a call needed to be made? Thank you for your time