BB called it a storeroom - I think it's used as both. Instead of going up a flight of stairs to the storeroom they had to turn right into the makeshift hallway that leads to the bunker.You can see a glimpse of it during the episode where they had to work in shifts. The first time Dan and Chad enter you can see the laundry. It’s directly next to the blue bedroom... which is why Marissa was caught attempting to push open that door earlier in the series.
The doorway is closed in that screenshot (white panel above Sarah's head). The blue couch sits in the corner between the bedroom and the doorway. It's where the fishtanks is/was.Does the entry doorway have a couch in it ? Never seen that before..