Blade Runner Scene

The scene I found most interesting from the film Blade Runner was the last scene involving Roy and Deckard.  It was quite peculiar that after fighting and trying to kill each other for a good amount of time, they would stop, sit, and end up not killing each other.  The two are fighting throughout J.F. Sebastian's apartment complex for a while.  Roy toys with Deckard.  Roy breaks his fingers then lets him go and he counts down numerous times to give Deckard time to run away and hide.  After the first couple times that this happened it was apparent that Roy wouldn't end up killing Deckard.  Deckard eventually makes his way up to the roof of J.F.'s building, where he is met by Roy.  In order to escape Roy, Deckard attempts to jump across to the roof of the adjacent building.  He misses the roof but grabs hold of a piece of protruding steel.  Roy jumps across to where Deckard is holding on.  As he is standing over Deckard ready to knock him off the ledge and kill him, something comes over him.  Deckard climbs up and Roy sits next to him.  Roy is about to die and knows it.  He didn't take Deckard's life because there was no point.  His mission was to find a way to elongate his life, which, according to Tyrell, is not possible.  Therefore, since his mission is not possible, there is no reason to take Deckard's life in the name of his failed mission.  He passes away and then Deckard is able to carry on with his life.