Originally Posted by The Guard
The easy answer is "Clark is still a young man". Young people don't always know exactly what to do in a given situation,
Here's the thing about that scene. I don't think Jonathan's first line, "Get your mother to safety" is an accident. Jonathan wants Clark and Ma to get to safety. Like its his instinct to rescue the dog, it's just the man's instinct to avoid putting people in harm's way, even his (for all they know) indestructible son. And we don't actually know the level of Clark's indestructibility at that point, so it's arguable that Jonathan could well think the tornado might kill Clark, who, as we see, Jonathan considers pretty darn important.
A young man who even in his pre-teen years already rescued people and demonstrated super strength if not invulnerability. So yeah, the faster young man going to the dog or seeing his dad delay and not trying to go to him sooner just seemed like poor staging in the seen. I see your point and it's a valid one regarding the importance Johnathan placed on his son and not wanting to place him in danger but Clark himself has already demonstrated a willing/self sacrificing spirit. So him making the call to run to his dad BEFORE his dad waves him off like when he's trapped in the truck would've seemed more in character. The scene fails to convince me that those specific circumstances would have ever occurred considering what we've already been shown regarding the people involved. Just doesn't ring true for me.
I get that a lot of people loved that scene and were emotionally moved by it. I think that's great, at least it worked for them. I was more like "wait what?! but couldn't he have just...that doesn't even...it was a stupid dog...but why..." Yeah it just took me right out of the movie. I'm happy it worked for other people though.