News outlets typically pride themselves on breaking stories, bringing you news "first" and yet only occasionally provide much context or background to the news. Even then, much of that kind of news is not truly vital to a wider audience. Still, news is news and if you want to know about the sirens or a helicopter there are places you can check.. and actually learn the same information news organizations use about  what is happening. 

Some things that might be of assistance if you are interested in Fire Dept and police activity around you.

1. The City of Seattle maintains a 911 log you can check (though this does not apply to areas outside the city except occasionally.. here: 

http://www2.cityofseattle.net/…/realTime9…/getDatePubTab.asp

2. You can follow the King County Sheriff helicopter people on Twitter here:

https://twitter.com/KCSOAirsupport or the PIO here

https://twitter.com/kingcosoPIO

3. Seattle Police on Twitter can be found here:

https://twitter.com/SeattlePD

4. and you can listen directly to police and fire calls from many jurisdictions here: 

https://www.broadcastify.com

News organizations can and do call other sources such as schools, and can ask police and fire sources for more information and greater clarity but for in the moment information these same sources we use might be useful for those interested in the most immediate information. One note of caution, police calls and even fire calls are sometimes in error and are highly preliminary in nature so bear that in mind before taking any kind of action.