There is a spot where you can walk under a gate that lets you walk into the tunnel that if you were to clear the instance, would lead you to the entrance.
What you need for this exploit is three gnomes, one of which being a warlock.
First you need to clear the first room of trash in Blood Furnace.
Here is a picture of the spot:
http://i11.photobucket.com/albums/a186/ ... sploit.jpgYou basicly just run up to that spot as a gnome and you can run right under it.
Here is a video I made on my friends mage of running under the gate:
http://video.google.com/videoplay?docid ... 6496959728 I used invis. to easily show running under the gate but you will need to clear the trash to actually do the exploit.
Once all three gnomes are on the other side of the gate you have to summon the other two members of your party and run up the the boss room (blocked off with another gate).
Then the last thing to do is pull the boss by having the warlock send his pet after the boss. As soon as the pet dies the adds will run after the warlock and go right through the gate.