Are fire drills really helpful?

Every school is trained for an emergency. Each room in a school has a laminated paper hanging on the wall directing the teachers down a certain staircase and across a certain street to make everyone safe. Being that there has been many terrorist attacks who wouldn't think that these drills wouldn't be helpful. Behind close doors many students feel differently. Students have began to feel as though fire drills are a way to get out of class and everyone takes their time down the stairs. How are we suppose to know when it is serious and when we are just practicing?
I believe that schools should start taking a more active role in fire drills. Teens like to take their time get separated from their class and wonder around outside. Drills teach you many things such as a way to keep yourself safe as well as others. They introduce safety and conduct in to the teens life in case of emergencies. Drills are very helpful and should be used with caution.