Since I attend college in an a state where campus carry is not allowed, I consider my best defensive tool to be situational awareness while I'm at school. Today, that increased level of awareness kinda came back to bite me when I was sitting in math class. I heard a muffled bang off in the distance which sounded like a firearm. At first, I didn't think anything of it until the banging came back and in bursts of several bangs at a time at a rate that sounded like a semi automatic firearm. Since the banging was far off, I figured I had limited time to react if this was actually a school shooter. Around this time, several other students became aware of this banging, and I heard some concerned whispers from around the room. Since I didn't want to raise the alarm and create panic for something that I was unsure about, I debated slipping out of class to "use the restroom" (get the hell outta dodge), but I decided against it. Ultimately, the noise went away after five minutes or so and class went on as usual. I never did find out what that sound was. While today was somewhat embarrassing due to the fact that I went on full alert and gave legitimate consideration to running out of class and calling the police, it was also a good learning experience. Perhaps the most important lesson that I thought of is to disobey my professor's rule that all phones must be turned off. If this had been a real situation, nobody in that room would have been able to immediately call for help. With all that being said, what would you guys have done differently and what other lessons can be learned from this experience?