Once you have found the Power Panel Parts, attempting to pick up the damned Parking Garage Key Card will trigger a cutscene, after which you will take control of Sherry. This section is only available when playing as Claire.
As soon as you gain control, turn around and pick up the Stuffed Doll from the chair. Examine its back to find a Picture Block. Use it on the device to the left of the door and solve the puzzle.
Inside, you will find a pair of Scissors. Use them on the wall opposite the puzzle to reveal a hidden passage. Go through the door, continue to the end of the hallway, pull out the drawer, and climb onto it to proceed.
Once you reach the Nursery, crouch to pass beneath the obstacles and go down the stairs in the Main Hall toward the exit... which, of course, is locked.
You can read Tom’s Diary on the low table in the middle of the colorful rug. Now go through the western door and follow the hallway beyond it. Do not worry about "him" for now. After going through the door at the end, you will be in a relatively safe room. In front of you, you will see a typewriter and ____’s Diary.
Move forward a little, walking at all times and never running. Once you pass the body on the table, look to the right to see the key you are searching for on the desk beside the wall.
After the cutscene, turn around, run upstairs, and enter the room with the cribs. As soon as you crawl beneath the toy castle, turn left and hide behind a crib so that you can see Irons when he enters.
The idea is simple. From your current position, it will be easy to avoid the police chief. He will walk to the other end of the room before turning back toward the entrance, at which point he will stand still for a few seconds. Use this opportunity to move to the opposite end of the room and hide beside the table.
Wait for the chief to move toward your position, then remain close to the tables and crawl into the gap beneath one of them. Do not worry: he will walk straight past you, triggering a cutscene.
Now crouch and approach the door. When you see him lower his head to wash his face, stand up without running and take the Orphanage Key from the lock. Turn around and hurry away, as he will spot you, then attempt to escape the Orphanage through the front door... or not. When the front door refuses to open, return to the western hallway and follow it to trigger another cutscene.
You will unlock the Hide and Seek Achievement/Trophy, obtain the Parking Garage Key Card, and regain control of Claire. However, you now have a new objective: Rescue Sherry from the Orphanage.
