Also, when it says 'chamber of Mazabul' was where Pippin knocked the skeleton down the well, the top legend shows it in #12, but only on the side view map. I know everybody will want to find the places where the movie (and book?) Events happened, like me, so please don't forget to also add #12 to the top-down map so we can find the room with the well and the coffin. Thanks!
I don't think the movies are under the IP that Free League has - and in the book Pippin didn't knock any skeletons down wells. He dropped a small stone down one, and that was in a guard room where the company rested, next the the '3 way split' where Gandalf wasn't sure of the way.
That said, the Chamber of Mazabul should be just off the "21st hall on the North side", on the 7th level, according to what Gandalf says the book.