After completing the entirety of The Organ Transport Box Puzzle you will now gain access to the Isolation Ward, where you can also find the Security Manager’s Office.
The office contains the body of the Manager, who has a LVL 3 ID Wristband on his wrist, and the third Puzzle Box.

Interact with the Manager’s body to grab the LVL 3 ID Wristband, unlocking access to all the LVL 3 doors that were previously locked off.
Don’t forget to interact with the Notebook next to the body to see the combination for the Puzzle Box.

Now head over to the Puzzle Box and you’ll discover that the buttons are now in braille, meaning it’s time to march back on over to the isolated cells in the Medication Room.
Once there unlock the door to Emily, the blind child, and a cutscene plays out.
After the cutscene it’s time to make your way back over to the Puzzle Box, but beware that you cannot use any weapons whatsoever while carrying Emily so get ready to dodge and weave around enemies!
Once there Emily will open up the Puzzle Box while you fight off the incoming swarm of enemies.
When that is done and over with, the Puzzle Box is unlocked and Emily will have the last part for the main escape door.