Spoiler warning

I really like the premise of this adventure and I can quite easily tie in the campaign protagonist (an ex teammate of the group) as another potential purchaser. Therefore I am gonna run this as my next adventure.

However, I forsee a problem with exiting. Putting aside killing Greel and figuring out that his amulet is a key, the solution is to murder the Haarlock scion and feed his blood to the Widow. I think my group will struggle with doing this. I can obviously get one of the more unscrupulous patrons of the auction to kill them but that seems a bit like handing the solution on a plate.

If you have run it, how did it work out for you?

My group came up with a rather unorthodox plan. They blew up the void shield generators, meltagunned the main door down and did a runner before the volcano went off. I know not quite how it is supposed to go but since one of the PC's stayed behind to initiate the generator overload I let it go. The description of the Alter of Fire sounded to me like a generator and somewhere else it mentions that the facility is powered by geothermal energy. The Techpriest set it up and the Guardsman stayed behind to initiate it.. It was one of the most inventive plans they have come up with in DH so I thought it would be a bit mean to say no. The meltagun came from a servitor that the techpriest then rigged up a trigger for, making it unreliable but still able to melt the doors enough to make them fall down.

Not sure that was what you were looking for but...what the hell.

Kaihlik

Just make it a point to instruct your acolytes very clearly.
I told them to find out as much as they could about the Haarlock line and the House of Dust and Ash.

So they inmediately went for the tomb and quickly figured it was important and needed a key.
Than they met Greel not much later and in his discription is the Amulet 1+1=2.

Otherwise, they need to loose some principles...