Also I forgot to say, if possible could you try to report that or any life-threatening situations to your parents? It'll be great so they can call the police or barangay captains/tanods to make the place safer
If you saw a person holding a gun for the second time, immediately do the Run Hide and Fight rule, where you run in a zigzag to make it harder to sh00t, evacuate and find a safe place to hide, warn other people around (best situation is with many people), and your final chance, is to FIGHT the sh00ter. If you have other people or your friends with you, you can call them to help attack the person