In a close shot We can see Cobb's face, he strarts to remember why he is here. Close shot again and we can see Saito, saying that he is waiting for someone. We can hear Cobb saying "Someone from a half-remebered dream" and we see Saito's reaction, he rembered him, he remembered `Cobb, but he thinks it is impossible, they were young men together and he is an old man now. A close shot to Cobb and we see him trying to remember while saying that Saito is filled with regret, close shot back to Saito saying that he is waiting to die alone, close shot back to Cobb he remembered he came back for Saito to remind him of something he once knew and we see the totem which continues spinning, that means they are dreaming and so they understand that this world is not real.