The albergue occupies part of the ground floor of a large municipal building. You need a key to enter the building and another to enter the albergue. When I was there I was the sole pilgrim and was given the set of keys and careful instructions in Spanish on how to leave the keys behind when I left to keep from being locked in. If I remember correctly after two years it was to prop open the outer door, go back to lock the inner door, drop the keys off through the inner door and then leave through the outer door, shutting it behind you and having it lock automatically.
I think it was this way because you needed the key to unlock the outer door even from the inside. I hope the renovations made this better.