We are told that Rava brought a gift to Bar Sheishach - finding him in a bathhouse with naked zonahs standing before him.
How was Rava allowed to enter such a place? Even if he realized only afterwards what was going on, shouldn't he have left immediately?!
I don't think that Rava realized that Bar Sheishach was going to be, shall we say, entertaining guests. It is possible that the Gemara means that these zonahs were in the bath of roses as well, and the roses or rosewater was colored, covering up the zonahs. Additionally, it is possible that Bar Sheishach was such a powerful officer (which is why Rava was giving him a present in the first place) that it would have been suicide to leave his house without answering his questions.
All the best,