I do think we're going to get a Yuri/Karaka fight on the 43d floor. Comments by Pedro suggest Karaka is waiting there. I don't think Yuri will die though, as SIU has said in the afterword/blogposts that she will be an important character for the "later half" of the story, and personally I don't think the story is at that point just yet.
Also, and this is just speculation on my part, but I think TOG is shifting towards the shonen genre. I just can't see important characters dying anymore.