Quentin and Rafe thought that Birch's murder would quietly fade into the past once the victim's body was tossed off Dante's Drop. Nicky's visit and discovery of the bloody pillow show that those sins will come back to haunt you, even in a lawless future.
Stahma took a pretty bold step in sleeping with Kenya, knowing Datak wouldn't approve...but her pillow talk with the NeedWant proprietor showed her to be a savvy customer who knows you catch more flies with honey...and keep your head, too.
Nolan's battle with Sukar atop the arch was epic, and Sukar's apparent invulnerability seemed like an insurmountable obstacle. But Nolan knows the way to win any fight: Speak softly, and carry a big hand cannon.