He just listens with a passive look on his face. 'Just doing what I was told to do' is a familiar refrain to him, from his own family for the last six thousand years (not that he's seen most of them in that time). But by the time Gabriel's done, Lucifer has the tiniest trace of a smile on his face.

"So. You don't know why someone else wants it, why someone gave you the order to do it, but you seem to be aware of why you want it. In this case, the two things just happen to be the same."

Which is a start. At least Gabriel had come up with somewhat of an explanation.