DON'T PANIC.

You cannot escape all responsibility for your panic. You need to get a grip enough to be understood.

You do know that the 911 operator needs to dispatch the right emergency response team. Then it needs to get to the right place. Just because you are using a cell phone doesn't mean 911 has a clue where you are. They also need to be able to provide information to said emergency responders that can help with their handling of the situation. And finally they can also provide the caller with any number of instructions on how to make the situation better, such as first aid to start, or how the caller can protect themselves from possible further harm. Panicked people aren't focused and can give all kinds of incorrect information. Getting them focused ensures the correct response to the correct place.