Compromise

Lucifer...did not want to do what the brain wanted him to do.

The very reason why he did not want to do what the brain wanted him to do is because it would make him look weak.

Lucifer would look as if he had done what the brain wanted him to do because...that was really the only thing he could do in this situation.

Of course, that was not the truth since Lucifer can just ignore what the brain said and he would be able to continue...trying to get what he wanted from the brain by using force.

He can even try to torture the young man right in front of the brain to make sure that the brain would give what he wanted.

There were many courses of action that Lucifer can take in this situation, and he did not have to limit himself to a choice that would make him look weak and thereby giving the brain a chance to think that he can take advantage of Lucifer.

That was why Lucifer did not want to do what the brain told him to do.