Where does Security Architecture fit or not fit with Enterprise Architecture?

In the video below on CxO Talk, I asked Edna Conway, CISO of Cisco about the architecures fit into each other.

In my view Security Architecture is a subset of Enterprise Architecture. However, since security is important at all levels, a Security Architecure gets deep into and can work in parallel with Enterprise Architecture. At the user level, perhaps we should know the threats that are out there.