RFID can also tell you who is in the building at any given time. So in an emergency, you can identify the areas where there might be people requiring assistance.
A former employer of mine introduced the electronic gates which are normally used on public transport. You needed cards to get in or out but you could jump the gate in an extreme emergency. They had a secure environment, but with ~300 employees, finished each day with about five discrepancies.
A major purpose of the access control system I previously worked on was to keep track of the number of people in every area, for safety reasons. Venues are licensed to have a certain number of people in each volume and access control records become important if there is an accident.
