The group arrives at the mysterious Smoak Technologies building in the simulation to find a portal back to the real world in episode 5x08 "Invasion!".
Oliver runs outside to stop the prisoner transfer and steals a truck to chase after them in episode 5x22 "Missing".
Source: What's Filming — Twitter
Chloe and Lucifer talk to employees at a social media company after videos on their website were linked to a murder in episode 2x03 "Sin-Eater".
Source: Larry Andreutti — Twitter