Use the Escape Route is the first quest of Chapter 2, "Fateful Encounters", in Final Fantasy VII Remake, taking place in Sector 8. After escaping Mako Reactor 1, Cloud Strife and Avalanche travel through the Plate Partition of Sector 8 to escape into the surface.
After a cutscene, follow Barret Wallace and Avalanche through the debris in the sewers. Though some parts are blocked by debris, the blue arrows on the ground indicate passable terrain. At reaching the end of the first hallway, open a treasure chest for the two potions inside, then head right to the next corridor. Once again, pass through the fork and the blue arrows, at which point Jessie Rasberry will set off a bomb. Regroup with the others for the bomb to detonate.
Once outside, a cutscene will commence. At the end of this, head up the stairs at the back-right to follow Barret, who will tell the group to regroup in the freight car home. This leads into the next quest, "Reach the Sector 8 Station".