I guess the conversation from Chapter 86 just ended, and then a robot (ERNINE) shows Hugo out. Hugo is well chuffed that he has a new lead on the case. He runs back through the underwater hallway and then back up the ladder and when he emerges in the bathroom there is a woman on the toilet. She (MAGGIE SUWANNAKINTHO) pitches a fit and Herman Kim almost beats Hugo up by accident but then realizes who he is. He teaches Hugo the secret knock so that won't happen again. Hugo then asks Herman Kim if he knows Margaret Ball. He doesn't answer but the bartender tells Hugo not to ask about Archivists. If you don't remember who Margaret Ball is (I sure did not!), she's mentioned later on down this page, just do a search.
And along those same lines, just in case it's important later I'll describe about Maggie: she's kind of down on her luck and working as a sort of highly specialized call girl, employed by Fedema. She's sad.
It's interesting that we don't learn the bartender's name. Is she the only person I can think of who we haven't learned their name? We met another bartender before, Estra Maxie if you remember.