What does this dream mean?

OK It started like a normal day in school. me and my friend were at the cafeteria and were talking about something. I went to the bathroom and find a lever that said DO NOT PULL and i pulled it and suddenly the wall started opening up in the shape of a box. I ran out and saw the principal and the administrators coming in the cafeteria. I go back to sit down but realize that the cafeteria is being evacuated. I go outside and see an explosion go off and my friends walking. I then realize i am also walking and my friends who haven't been converted(don't no what it means) were running but me and my friends that were converted were walking. Suddenly another explosion happens and all of my friends and me fly into the air except a girl that i liked. While i am flying through the air i hear a rumbling noise and my friend(miranda) turns around and sees a stampede of kids heading toward her direction. She tries to run but isnt fast enough and gets trampled over by the kids. When i land i find out that i landed one mile away from the school and my head is cracked. My sisters appear and tell me miranda died. I am shocked and run back to the school leaving my smirking sisters behind.I find out miranda is on the ground but not moving and has bruises all over her body. Thats when i finally realize that blood is running down my head and covering me. The dream then ends with the ending of the song "Danger Line" and me crying over mirandas body. Can anyone tell me what this means?