The dream and romance of the road has gone and been replaced with something deeper, darker and more complex. Dean doesn't stick around for that, and leaves Sal sick in Mexico City, making Sal realize once and for all the limits of their friendship. In the end, their positions have changed. Sal is strong, confident, in love, and Dean is incoherent and lost. Still, he loves Dean. Dean is the falling star Sal was chasing; Sal will always remember and value the star at its apex, when it presided over a whole world.