small talk usually works well in a situation like this. how about trying to tell the interviewer a joke, sharing a piece of news or starting from something less "relevant" to your "qualifications" to b-school? e.g. quotes are one of the best resources you could use to facilitate a conversation. it could be from your favorite book, or lyrics, or person, or even movie. 1, a nice quote substantiates your point more effectively. 2, what you choose to read, listen and watch is a reflection of your personality. 3, don't depend on this but you might be able to find some common interest with your interviewer.
feel free to be more spontaneous and more engaged to the "conversation" , rather than treat it like a testimony. think about it this way: if you want the interviewer to take you as someone special, act like one.
but Im afraid the talk between me and adcom was too casual and relax which made me wonder what aspects they want to measure in the interview. you know, our talk was a little far from an interview. Will this bring negative influence to my interview? though the atmosphere was really great