code: http://blacksteel.nma-fallout.com/tutorial/code4.txt
Use some scenery trick: place broken elevator picture with rope and in the same place elevator shaft without rope with that script. To place one scenery on second: press M in mapper and hold mouse button on scenery, then move it to hex where already is something. When you place one picture to other, visible will be only this second. Script just remove one picture and appear second picture which is behind. In practice: if you use rope on broken elevator shaft it will disappear and you will see second picture: shaft with rope. This second shaft must be "stairs" obiect (make new scenery proto) so when you use it, you will climb level down/up.