I meet with the 3 managers that were all my potential boss. The interview was more informative than anything. I was not a candidate for a hardcore consulting job, I would be working for the Field Operations team that manages the real estate and internal resources of the firm. All of the people I inteviewed with were nice. The asked me to walk them through my resume. They then talked about what they did. Then we had a discussion about it. It was important to be able to speak intelligently about what they. For me, the were impressed that I already knew the lingo and had an Idea about how the company operated with from my research. The second most important thing was to be likable. The interview wasn't the type to make one nervous but they told me later that my condifence and amiability were a large part of me being a good candidate.
Listen when they talk, ask insightful questions, and relax because they are nice and they are people just like you and you will be fine.