"It is because of what I would do after I sort this situation in the Warmester Denoble House." Lucifer said.
Naturally, since Lucifer had the plan to use Oumu as some kind of bridge so that he would be introduced to the Warmester Denoble House, he intends to sort the situation within the Warmester Denoble House first.
There were still too many unknown factors within the Warmester Denoble House, which might cost Lucifer the puppet head, Rouge, if he leaves right away without sorting the situation within it.
Of course, his subordinates knew that, but what they still didn't know is what Lucifer planned to do after sorting the situation out.
Even though they now know that Lucifer is Lucifer, though they still don't believe it, they still do not know what Lucifer is doing.
And if they do not know what Lucifer is doing, then there might be some miscommunication between them and might hinder Lucifer.