With my experience as a law enforcement officer I expect the app to be user friendly and prompt. When calling 911 with an emergency there are protocols and procedures that are required. The app should be helpful to those in danger in a fast mannerly way. An app where things can be communicated within a few sentences/words and a section where information can me filled in regarding the shooter. I also believe an app will be helpful for when presented in that kind of situation. You can quietly access the app and report the problem, rather than calling and being heard or found if hidden.