The final key handed back ends access more precisely than it ends attachment.

Endings are administratively clean and emotionally slow. Handing back a key settles exactly what you may do from that moment and settles nothing about the fact that you still know which floorboard creaks and which window sticks. Legal endings and felt endings run on different clocks. Being unable to enter a place does not remove the place from you.

After a formal ending, allow yourself to feel attached to something you no longer have access to. Walk past once if it helps, or do not. The paperwork finished on a date, and you are permitted to take longer.