COLOSHOOTR

Hey I noticed you were in an active shooter forum. I have a few questions if you don't mind me picking your brain. I'm a Military Police Officer stationed in Hawaii right now, used to be Texas. We're going through active shooter training this week. The instructor was teaching us that going through a building with a 4 man team to use the "T" method. Three officers line up in the front, and the fourth pulls rear security. How accurate is that based on your training? He said it was that or the diamond formation.
My next question is they're pushing hard for "sleeper" shooters in our training and scenarios. I've tried to research a real life active shooter with a sleeper shooter that waited for LEO contact before becoming activated but came up empty handed have you heard anything like that? Thank you in advance for your time and knowledge.

A Gentleman of his word and they are hard to find these days. Stay safe