The writers couldn't figure out a better way to write Quinn into another episode. I mean she was only able to do 3. The first one when they came home for the holidays was perfect, and the one where she came back for Mr. Shue's wedding was perfect. But this one? It's just kind of unrealistic that Kurt would call Quinn all the way from New Haven just to have a girl talk with Rachel.
HoennMaster And the strange thing is I had to rewatch season 4 to realize that New Haven is only an hour away from New York and to realize that Santana was in Kentucky. lol I thank you for this :)