Final answer:
The door to an apartment that provides access to a fire escape will likely have safety-compliant locks and multiple keys to ensure accessibility during emergencies.
Step-by-step explanation:
If a fire escape is accessed through another apartment, the door to that apartment will often have additional requirements for safety and accessibility compliance. In many jurisdictions, building codes would require that this door remain unlocked or be able to be opened from the inside without a key to ensure that occupants can access the fire escape during an emergency. This practice aims to prevent tragedies like the ones where locked doors led to loss of life as in historical building fires. It’s possible too, that multiple copies of the key may exist as a safety measure to allow various individuals quick access, such as maintenance personnel or legal practitioners with adjacent chambers.