Well this one just gets me, man oh man what a beautiful line for a ballad. Oscar starts off going down the Bb7 dominant bebop scale but uses a Tritone sub for the Bb7, turning it into an E7 which makes the G# the 3rd. He then proceeds up some chord tones, the 5th, 7th and 9th to a nice 3rds interval pattern at the top and finally resolves to Eb. Stunning line.