From Diablo Wiki
- From the Quest Selection screen take quest 9. The Imprisoned Angel > Cursed Hold.
- Take the Waypoint from Tristram to the Halls of Agony, level 2.
- Locate the exit from level 2 to the Highlands Passage. Don't go through the door yet but check your map for a yellow dot below your position. If it's there A Stranger in Need featuring the Tormented Behemoth has spawned.
- If there is no yellow dot go out of the doorway into the Highlands Passage to get the Checkpoint then leave and "resume game"
- You will begin in Tristram with a Waypoint waiting for you that goes back to the Highlands Passage. Go back into the Halls.
- The event will only spawn next to the exit out of Halls of Agony (level 2), if it's not there don't bother looking anywhere else on the level.