What was that talk about the Nightingales sticking together? What was all that "we need our combined strength to defeat Mercer"? Were you lying to me, Karliah? Why haven't you been honest to me about your motivations, Brynjolf? I feel disappointed. After all we have accomplished together? Rebuilding the guild from its ruins. Proving Karliah's innocence. Tracking down Mercer Frey. And still, you walk out on me in Irkngthand?
How dare you calling yourselves comrades? How can you even look into the eyes of your mirror images? Have you absolutely no spark of honor in you at all? Truly, my disappointment can't be described in words.
To save yourselves a bit of honor, yes, you have returned to face Mercer with me. Only to get caught in his treacherous spells. Your help was much appreciated. But I'll be honest with you guys. After your previous deeds I seriously considered not helping you during the cave in and letting you drown. I did not if only to prove that in contrast to both of you I'm a reliable person.
For those not knowing what I'm talking about: This is about the following bug in a particular quest in Skyrim.
(Xbox) Brynjolf may leave his post and walk to Riften as soon as you enter Irkngthand, rendering the quest non-completable
Update: Quote removed, I was sloppy and linked the wrong bug. Apologies.
Update 2: Got the right quote now.