Dream About School Fire Shooting Tense Encounter With Stranger

I had a dream I was at school then suddenly there was a fire alarm and everyone had to grab their stuff and leave and I was the last one out. And then once we got out we just stood at the entrance of the building with our things because it wasn’t actually a fire it was a shooting (even though I go to a private school in Scotland). Afterwards we all go out in groups and my group is with a bunch of people I don’t talk to except a girl in my class called Sophie. The leader of my group was one of the lunch ladies. She has a Russian accent in real life but in my dream she had an American one. She has to go to the math building to call someone and she tells us to stay outside and if anyone approaches us we don’t say anything except that ‘we’re tired’ and we’re ’bad At school’. So she goes off to the math building and we are left by a statue. A bald man with a bunch of military equipment runs over and ties to start talking to us. My friend, Sophie, turns around and doesn’t say anything. I however turn around and face plant. Sophie then tried to entertain the man by telling him that we were left stranded because we were bad students. The man tells her to come over and he hands her a grenade he tells her to place it on the ground and pull the pin. Sophie only places it on the ground. I thought she already pulled it so I start running but then he tells me to come back. All of a sudden you hear the lynch lady in the call and she’s talking really loudly. Me and Sophie, say that it was a girl called masie (a girl who doesn’t like me in real life) to make it sound like the lynch lady was a student. The man walks over to the math building and ‘masie’ finish the call and walks over to him and starts trying to negotiate things. All of a sudden I wake up with a fast heart beat.