The line drive was plenty deep, He had a brain fart
Or the 3rd base coach wasn't screaming at him to go. Just absolute stupidity.
Saw this later and it's definitely on Church. He'd started about a third of the way down and for some reason decided to creep down further as the ball was carrying. So he was halfway down the line and had to run back, was almost back to the bag by the time the throw was made.