A gunman shoots up City Hall in episode 5x13 "Spectre of the Gun".
Curtis and Rene visit a support group to learn about James Edlund in episode 5x13 "Spectre of the Gun".
Oliver heads to the hospital to stop James Edlund from killing people in episode 5x13 "Spectre of the Gun".
Team Arrow sets up outside A.R.G.U.S. to stop Helix when they show up in episode 5x19 "Dangerous Liaisons".
Dinah is delivering some documents to Councilwoman Pollard when she saves her from a sniper in episode 6x05 "Deathstroke Returns".
Rip Hunter, Dr. Stein, Kendra, and Carter walk to the university where they are looking for answers in pilot episode "Pilot, Part 1".
Sara, Jax, and Stein toke up with a young Stein and then steal his prototype in pilot episode "Pilot, Part 2".
David leaves the mental hospital in Syd's body and sees three strange individuals getting out of a car in episode 1x01 "Chapter 1". Lenny has therapy sessions with all the team members in her office in a dream version of the hospital and David is denied pie in the cafeteria in episode 1x06 "Chapter 6". Lenny waits in the office for David to weaken so she can take over in episode 1x07 "Chapter 7".
The group rushes downstairs past more dead bodies in episode 1x05 "Chapter 5".