"I Don't Wanna Go Home"

Last night, I was thinking about "I Don't Wanna Go Home," specifically a line at the end of the first verse:  "You should have stayed on the outside (Lookin' in)."  As the parentheses indicate, the "lookin' in" is sung by a different voice.  Because there are two different vocal parts here, there's a sense of separation (which the narrator is retrospectively wishing for).