In many cases they have no idea what the scene of an incident looks like, and what they’re actually going to have to deal with, until they get there.
The WMFS have been working on an app called 999eye, which could let you stream video of any emergency situation so firefighters (or the police) could know immediately what the problem is, and how best to respond.
The app would also find and broadcast the location of the incident, which would be incredibly helpful if people have little or no idea where they are.
They are currently looking for other emergency services to join them in supporting the launch of the app. If you’re an emergency service (we assume even emergency services need the occasional internet LOL), you can sign up at 999eye.