“I just heard what sounded like three automatic gunshots….”

Episode 19 Dallas PD Gang/Swat/Intelligence Darian Loera

Detective Loera has succeeded in every high profile position he’s worked in. Starting with the Gang Unit as he learned from one of the legends in Norm Smith. He then joined Dallas Swat and was involved in two critical incidents and nearly lost his life twice. He now investigates threats of life in the FBI Joint Terrorist Task Force. 

Definition of Phrase: "Running in the stack, being in the stack" refers to being in the tactical lineup in operation approach or execution of an operation. Operators are designated by command and stacked (lined up) in order and have specific assignments for each op.