My comment in that thread is below:
It's interesting how such a simple concept as a key can be so profound to different people in different ways, as evidenced by its relevance today in ways that would have been unimaginable to the ancient people who wrote about keys.
I like the framework of opening and closing, but I also like the purpose of most openings. It's one thing to talk about opening a door (or gate) in order to enter a room (or restricted area), but it's another thing entirely to talk about opening a door or gate with the purpose of seeing / experiencing what is inside the room or restricted area. In other words, keys, primarily, aren't about getting into a locked space; rather, at the core, they are about access to something of value - whether that be gold or an elite group or solitude or safety or increased light and knowledge. It's not the room that is the focal point of having keys; it's what is inside the room and the benefit of what's inside the room.
That's easy to forget that in the myopia of "getting into the Celestial kingdom" - or any other location. In Mormon theology, the ultimate destination is a condition - and the key generally gets someone on the path and allows her to walk along the proper path - having her condition changed as she walks. I believe, therefore, that life's journey is comprised of a series of keys - and, in a real way, I believe the final destination has no key and no entrance, Rather, it is where someone ends up after all the gates have been opened and the veils parted and the realization hits that she was "there" all along. Thus, theoretically, there is one key chain holding copies of the same master key.
At least, that view works for me right now.