Find the fusebox and open the airlock | Chapter 12: Regina Metro: LL Guide

Climb down the car and go right. Collect the filter, and open the door to the right. This location is very similar to the optional areas that you have visited earlier, because, also here, you will be encountering spiders. Start by turning on the oil lamp attached to the wall on the left.

I recommend against wasting ammo and time to eliminate the spiders. Instead, sprint all the way through the linear corridors to reach the fuse box shown in the above screenshot. Interact with the box and restore power to the airlock.