For me and for I'm sure any actor, each role is a different challenge to prepare for in a different way.
A lot of knowledge in any kind of an organization is what we call task knowledge. These are things that people who have been there a long time understand are important, but they may not know how to talk about them. It's often called the culture of the organization.
I visited the Pentagon a few days after September 11, and I still remember so vividly the smell of terror surrounding the entire building and complex. I was angry that such a brutal act of violence was committed against innocent people.