Well you can take it as you wish rules are : it takes one complet turn to move from one level to another. So if a model enter the elevator, it can't move on the next turn. Then it can move on a subsequent turn. It's the same to call the elevator if it is not on the same level than the model : it takes one complet turn for the elevator to move from a level to another. To call the elevator, a model must facing the door and it can't do anything else than moving to facing the door (no close combat and no fire with a weapon). Firing in the elevator with a zone effect weapon (like a missil launcher for example) will destroying it, and it will killing all models in it instantly. Those rules are available for Space Hulk and Space Crusade
I just found all this cool stuff and now I'm having to fight the urge to get some Space Hulk miniatures I think I will just have to give in to the temptation and get some and paint them up, just so I can make use of these excellent tiles
When men meet foes in fight, better is stout heart than sharp sword.