Assumption: You are a teacher in charge of a classroom. Someone with criminal intentions comes onto campus with firearms.
Per protocol you lock the door, move the kids away from open windows, making the room appear empty. You have the kids low and quiet. Somehow the perpetrator is able to open the door and come into the room. You and your charges are now under dire threat.
Assumption 2: You have a firearm and training in the same situation.
I believe assumption 2 would offer better protection for the kids under your care.