Actually one of the things that makes me insane about Grace and Carl's dynamic in the movie is that while not explicitly, Carl is clearly cast/written as the Intimidating Secret Agent (I say cast because let's be real, he was cast as a Black actor and there's some implications there given his role is initially to be intimidating and scary), and yet Grace trusts him and relies on him practically from the get go. Who does he ask if the sun is really dying? Not Stratt, Carl. Who does he look to for confirmation that the Petrova Task Force is moving out now that they know the dots are in fact alien life? Carl. Grace trusts and relies on Carl, takes his encouragement and advice, runs with his theories, long before he has that same level of faith in anyone else.