Just some edits, the first two just being incorrect mistakes:
Head back downstairs and turn to the right. It's really dark over here, so just keep walking straight until you get to a door with an "Exit" prompt. This will take you back to the area we started in. Walk straight back past the two security cameras and on the right hand wall under a bunch of lights, you'll see an elevator. Enter the elevator and turn to the left. Interact with the panel and you'll see three prompts come up with arrows representing the floor you want to go to. You need to click that direction on the D-pad to get to that area. We're going to click left on the D-pad to take us to the second floor.
Needs to be changed to "to the LEFT".
Hit the button and after a scene you'll be back outside the church. Head back down the ramp and make a hard left and head back into the building you first entered at the beginning of the game. Once inside, interact with the same pills you interacted with at the beginning of the game to get the special pills achievement. Turn around and exit through the door you came through, then head back to the elevator and press up on the D-pad to head back to the third floor.
This would, again, be a "make a hard RIGHT".
You'll come into a room and see a big white ramp and a bunch of pillars you can interact with. You need to interact with as many pillars as you can until you see the prompt "[Press A Button] to feel the irony". Once you get this prompt, interact with it and head up the white ramp. Once you get to the top, you'll see an illuminated typewriter. Interact with it and you'll get your last achievement:
Not so much tall pillars as short little mailboxes, but whatevs you know.
Fear is the mindkiller.