Reddit:
One person goes to each tower to clear the boomer knights.
Two people on each side work their way to the Deathsinger room clearing out adds on the way, taking down the shrieker, etc.
At this point, my team sends one person into the Deathsinger room to clear the two knights that spawn, while two people go to their respective ogre rooms, and the remaining player (of the four) goes to the middle to clear out the trash mobs that come out. Meanwhile the there are still two players in the upper towers to kill the boomer knights.
The middle player can then down the swordbearer and run it up.
Most of my group runs Razelighter and we consistently finish in ~1:50 even while making some positioning mistakes along the way.