They are the lifeline on the other end of the telephone. They listen, take notes and gather as much information as they can in seconds.
Those seconds count, especially in matters of traumatic injury or fire or criminal matters happening in real time.
Ask anyone who has worked in a field where a matter of seconds didn't apply. Put them behind the desk of an emergency dispatcher and it is a whole other level of work. An entirely different reality. Those who call emergency communications their profession say there's really no other job like it. And for good reason. It's a job where it could be relatively quiet one minute and the next, six calls for help fly in, each unrelated, and each at different locations.
In other words, every shift experience is different, and there's little room for error. It's why 911 dispatchers are considered the "first" first responders to an emergency.