With all the confusion and terror after the shooting and the Sheriffs of Cowards County quaking outside, I would think he had time to change. And we really don’t know what this “body Armor” was, it could have just been something fake but scary looking. I doubt that people in a state of fear really looked that close, even if they really knew what to look for. In Cruz’s little video he is wearing an olive drab vest not full metal body armor, so what did he have and what did the teacher actually see?