From the Item Box room on the second floor, head back to the balcony. Go through the door directly across from the Item Box room (using the Armor Key). This leads to a long hallway. Be cautious, as a zombie might be patrolling here. Follow the hallway, ignoring the first door on your right for now. Enter the second door on your right. This is a small library. On a shelf, you'll find the Shield Key. This key is crucial for unlocking more doors. Also, check the other shelves for any hidden items. After picking up the Shield Key, a zombie will likely burst through the door you entered. Be prepared to fight or quickly exit the room and run past it. Conserve your Shotgun ammo if possible.
