1.) Make sure you have the spell "Hellfire"
2.)Take off all gear that have give you stamina...(You want as little hp as possible)
3.)go to the locked door (Entrance to Scholomance)
4.) Now, Once you are there...Use hellfire until you are dead
5.) Bring your ghost back to your body and go through the door with your ghost and res behind the door.
6.) And there you have it, A entrance to a instance that has a very annoying chain to get the key to
7.) Enjoy....Just try not to repost this as blizz. will probably make a invisible barrier to disable the ability to walk into the door with ghosts.