On this spoiler free page of our guide To The Last of Us 2, we have prepared a walkthrough of a stage in which Ellie and Dina return to the gate with fuel (in the Seattle Day 1 chapter) in order to open a passageway leading further into Seattle.
Once you've searched and explored the entire area, you can return to the Gate East 2 to open it by using the fuel. Remember that this is practically the last moment to turn around and visit the side locations available in this area. Go through Gate East 2 - use the 5345 combination.
As you walk forward you'll notice that one of the infected jumps over the wall and runs straight into the hotel. Follow the monster, and you'll enter the grand hotel. Inside you'll find some infected runners who feast on a corpse. Sneak up on individuals and kill them quietly. You can kill the remaining group with, for example, a Molotov cocktail. After the battle, go to the door and walk through it.
Climb the stairs and visit next rooms. In one of the rooms you will find a corpse, which contains a code to the next gate. After that, follow Dina, who will lead you through the balcony. Get back on your horse and fly to Gate East 1 - approach the generator, while Dina enters the proper code to the gate.
This is the last moment to explore other nooks and areas of previously visited locations. Once you cross through the obstacle shown in the picture above, Ellie and Dina will come across new enemies. After that moment you won't be able to return to the previous areas.