WASHINGTON (WUSA 9) -- This is the way it should be, two sisters talking like sisters.  

"Every weekend we go over each other's house," says Jordan.  

It's a clear evening at Wilson High School in northwest and Jordan Dickerson and her sister, Robin Jeter, laugh and giggle at pictures of their youth. They have a right to be giddy because they're making up for lost time.  

"I come up here almost every day," says Robin.  

The sisters are together now but for so long their lives were separate.  Jordan, a junior at Wilson High School, was adopted shortly after her birth.  Robin, a senior at Friendship Collegiate, bounced around from her biological mother, to foster care, to a legal guardian.  For 17 years they lived in the same city, played some of the same sports, but never crossing paths.  

QUANTICO, Va. (WUSA9) -- For the first time, WUSA9 witnessed a drill at Quantico where first responders practiced how to respond to a gunman on base. 

The scenario: A shooter unloads inside the gymnasium at Quantico Middle High School.  The shooter is actually an active duty Marine, including all the people that are pretending to be shot. Meanwhile his pretend brother, a second shooter has now barricaded himself inside the cafeteria but not before planting a bomb inside a classroom. 

In the real world, this would be about as bad as it gets. But, that's exactly what this drill is designed to stimulate. 

The drill has been in the works since April 2012. The goal of the drill is to learn from it and improve their procedures for the future.