According to Zach Braff, he was mad at Sarah Chalke during the filming of the episode's final scene. When Carla, Turk and Elliot joins J.D as he relaxes in the park, Zach interacts with the other two actors and doesn't look at Sarah.
The short clip of J.D. with Death is a reference to a Connect Four commercial from the 90's. J.D. has eight tokens, whereas Death has only six. This could be an indication of J.D. trying to cheat death.