It's one of the few quests that you can fail, meaning you essentially have two ways to complete the quest. On my most recent character, I follow Logrulf into the abandoned house, rushed ahead of him, and waited at Molag Bal's altar.
I planted an arrow in Logrulf's skull just before he tried to complete his ritual. He fell right on top of the circle where the blade trap would have enclosed him. SO, I killed a follower of Boethia, and spit in the eye of Molag Bal, not allowing him to claim another soul in Oblivion. So close, yet so far away.
Granted, I cannot get Molag Bal's mace to round out my Daedra collection, but it somehow felt...good...to throw a wrench in his plans. It's unfortunate that there is no reaction from Molag himself.