Woman: "Yes, this is right the entrance"
Man: "No. We have to use the other entrance. We're not allowed to go in this way."
Woman: "Why not?"
Man: (Pointing to a sign on the door) "Look, it says there - guide dogs only".
Obviously a joke.

Woman: (Frustrated) "No you idiot. It means dogs aren't allowed in the building unless they are guide dogs with a blind person"
Man: "Oh! Yeah! Of course. Ha ha!".
I am guessing the woman was the person to be assessed for her physical disability, but perhaps her partner should also have been assessed for his IQ.