2E is best understood as:
- for landside purposes, 2E is the terminal
- for airside purposes, 3 concourses exist - K, L and M. You can only be in one concourse (your departure one); the part between concourses and arrivals (except a small number of arrivals from clean origins) is essentially landside*

*not strictly speaking - but it's not within the secure area. Can be understood as "landside but behind passport control".