Recently, some friends and I were attempting to go through Blackrock Caverns at increased speed. We wanted to skip the 2nd boss, and go to Steelbender, and then to the last boss.
Basically, just skip her, clear trash as normal, and have a rogue (stealth), invis. mage, or a soul stoned tank charge through, and click the Twilight Portal on the other side. Once they've touched it, everyone else in your party can go through the one at the top, because it becomes active. (Simply teleport in / out for a quick entry to the front).
Normally, it's impossible, because of all of the zealots blocking the way, and Raz will not appear to help until you kill the 2nd boss..
Let me know if you have any questions!....