In November 2008, a group of 10 well-trained terrorists with good communications systems and a well-coordinated plan essentially held Mumbai, the largest city in India, paralyzed for more than 24 hours.  

In contrast, fire/EMS hasn't followed suit. The current standard fire/EMS response to the active shooter is to stage in a secure location until police mitigate the threat and secure the area to create a scene safe for fire/EMS operations. But there's a basic problem with this response:While waiting for a secure scene, those injured inside the building aren't receiving care and are dying from their injuries.

Source: Courtesy of JEMS