Ruiz figures his work here is done, and lets Linder close his door. Notice how Linder didn't say anything to the nice policeman about the intruder in his apartment whom he had to brain in self-defense? Avoiding the official questions that would raise must be worth the inconvenience of dealing with this him. Otherwise he's just panicking, which I can also see.
Going back into his apartment, Linder sees that Calaca's eyes are open and he's looking around, but that's about all he can manage. So Linder picks up the iron one more time, and when he's done with it, Calaca's eyes are still open but not moving any more. And Steven Linder is probably going to need a new iron.
Back at the station, Ruiz rests his weary head on the table while Cross wishes aloud that they could tap Frye's phone. She repeats her suspicion that Frye won't tell them if the killer calls again. When Lieutenant Wade happens by, Cross asks how long the FBI will continue shutting them out, and Wade says it could be a while. So by all means, Hank, let them keep using your space while they do it. Ruiz grumps that he thought they were all one big happy team. Wade says he owes his own foul mood to his need for a root canal, and asks what's up with Ruiz. "He slept on a bench. In the back room," Cross says.
Ruiz says he can speak for himself, and tells Wade, "I slept on a bench in the back room." Wade grins, "Well, you got me beat," and proceeds on his way. Cross asks Ruiz what he and his wife fought about, and Ruiz seems pretty annoyed that she doesn't already know. "Sonya, you gave me my wallet back right in front of my wife…I dropped it at another woman's house?" Cross asks, "You had sex with Charlotte Millwright?" Whoa, check out the master detective putting the clues together. She is on the case. Ruiz says yes, and Cross reminds him, "You're married." "Yes, I know," Ruiz says. For now.
He gives her a little news flash: "We're partners. Partners look out for each other. That's an unwritten rule." I like how he puts the emphasis on "each other," because there has been some protectiveness going on, even if it's one way. Cross seems to be struggling with this whole concept, so Ruiz sighs and tells her to forget it. Despite this, she's clearly conflicted; on the one hand, she doesn't want Ruiz upset with her again, and on the other, she wasn't the one who cheated on his wife. So she makes him an awkward offer to let him sleep on her couch tonight if he likes. And that's called splitting the difference.