After 5 minutes, we (fiancé and I) were called to the window and asked to provide all the paperwork (application confirmation, medical, police report, birth certificate, I-134s).
We then waited 20 minutes to be called to the little side room where both of us were asked a series of simple questions (why K1 vs spousal visa, when/how did you meet, what do you do now and what do you plan to do in the US).
We were told passport with the visa will be given to the courier for delivery tomorrow.