It's very out of focus. Looks like it was scanned from somewhere. His white shirt also looks weird, like he has no right arm and his hand is just jutting out
Very weird outfit... is there more to the story that would explain the outfit?
Your description of the shot says that his attention was called back... I take it he saw something that made him pause and have another look? Seems kinda unnatural to have gone so far past it before looking back.
Looking at it without your explanation, I would think that a child suddenly called out to him from behind... or something dropped... a voice a sound...