An emergency response system of a premises uses an egress agent or application installed on mobile communications devices of users to provide evacuation instructions that are specific to the location of the user. The egress agents determine the location of their device and may determine an evacuation route from premises plans stored in the device or by transmitting their location to a server and receiving evacuation instructions from the server. Tracking of the devices along the evacuation route provides continual updates as to the relevant safety of an evacuation route.