Sanctuary is a very busy dungeon and reaching the elves at the far end can be very difficult – unless you know of the underground route!
From the dungeon entrance follow the eastern wall until you find the way down. Marked with a stairs on the map, find the hole to drop down.
Once underground, follow the path marked on the image below. There are traps on some passage ways!
The exit hole is close to the named creature ‘Chiikkaha the Toothed’. Emerge from the hole, marked with stairs on the above ground map, and follow the eastern wall until you reach the elves’ village, enter near the center of the wall.
On the return trip, when following the marked path underground, turn right at the sharp bend and move towards the point marked with an X on the underground map. Although there is a turn to the east before you reach that point, do not turn earlier.