From what you described it seems like the consultant liked your profile so you're already on a good track.
I would use this conversation to understand the process in the office you're applying to, his view on the office and on the company overal. These three topics will help you understand practical details but also more qualitative info that would be harder to get from an HR person for instance.
Expect this interaction to be an informal conversation which means that you will probably also get some questions (I would ask them if I was him). I suggest that you browse the corporate website for the culture pillars and the vision 2020. Understanding the culture can help you understand/answer how you can be a fit and the vision will help you understand/answer why ATK is attractive.