"Dearest prisoners! Esteemed guests!" In Selil's palace, those two often meant the same thing. "Congratulations. You were spared a death so that you can live for me. I can tell you right now that if you don't cooperate, it is going to be absolutely terrible in every conceivable way. If you do, however, then you can perhaps ascend the ranks and maybe even live somewhat contently within my glorious empire."
From there, he sent his guards to split everyone up into groups of a few hundred apiece, sending each to a series of rooms dedicated to deciding what kind of slave pit they'd be working in for the rest of the foreseeable future.