I figure the adults at the Sandy Hook Elementary School had twenty seconds to respond to the armed intruder on December 14th, if they were going to save any of the children in their care. That's all the time it would have taken Mr. Adam Lanza to step through the shattered front door and walk to the nearest classroom and start firing and killing first-graders. It took him a little longer than that because Principal Hochsprung and Mary Sherlach got in his way...but not for long. He just shot them dead and continued on.