How did they make the "bloody elevator" in The Shining?

I thought that the set was a miniature or something until I finally saw “The Making Of The Shining” documentary and the film crews were SWEEPING THE FAKE BLOOD AROUND THE SET. Since Kubrick always kept everything to himself and went out of his way to “destroy the evidence”(ie. burn each and every single unecessary bit of footage that he didn’t like) we may never know. Or will we?..

Anyone have any guesses?

Well, just build a set with a watertight closet made up to look like an elevator car at the end (say, line it with clear plastic tarpsarranged so that they’ll come apart at the line between the doors), fill it up with fake blood, and open the doors. Simple enough.

An interesting aside from