Outlast 2 has four main named antagonists, three of which actively hunt you down. Val, the creepy person above who licks your face, will encounter Blake in the mines, as he tries to shut down two electrical wires to clear a path to the next area. Since Val will kill you in one hit, this is a very tasking segment and one false move can put you right back to the start.
When you first get into this area, you'll notice the floor is filled with waist-high water. Once you're in the water, hug the right wall as you progress forward. This will take you to a table with a battery on it, grab that batter and proceed. Once you get to the next open area, continue to hug the right wall.
You'll see the wires hanging down on the right, and an L-shaped wooden wall in front of you, and, very soon, Val will come down pathway from the left corner of this area. Hide behind the L-shaped wall. Face him, and as soon as he progresses to the other side of the L-shaped wall, crouch under water and swim underneath the wall to your right. Once you're through to the other side, stand up (making sure he's no in line-of-sight, turn around and flip the switch.
That's just one out of two switches, though. After this one is flipped, move immediately forward into the pathway from which Val entered that area. Once you get through this narrow pathway, you'll see another L-shaped wall to your right. On the other side of that wall is the second and final switch. Flip it.
After flipping it, immediately go back through the pathway you came. Do not hesitate whatsoever. If you wait until Val gets into that second area, it becomes very difficult to avoid him. As soon as you're to the doorway of this first area, crouch underwater and retreat to the area with the first switch.
Once you see Val go down the pathway, immediately move under the wall to your left, and run through the passageway that had the live wires, which you now shut off. Continue straight down that path, and you'll find yourself safe from Val.