She tells him to put it down, and he says something about how he likes to kill up close. "I will shoot you," she says. Childress grins, and believes her, and pulls the trigger. So does Cross, at the same time. Both of them go flying backwards, sprawling and coughing, so Childress must have been wearing a vest as well. Ruiz runs past Cross, calling her name and pausing only to touch her shoulder before delivering a flying tackle to Childress, preventing him from reaching his dropped gun. As they fight, Ruiz roughly relieves Childress of a knife he's drawn, then gets his own borrowed gun at the base of Childress's neck while Wade and Cooper come running up. In the meantime, Cross has struggled to her feet, but collapses into Wade's arms. Ruiz asks if she's okay, and after ripping open the Velcro on Cross's vest, Wade confirms that she is. All things considered, that was probably the best possible outcome. Except for Stokes, 'course.
At the police station, an EMT has just finished treating Cross at her desk. Ruiz, with his head finally clean but blood still on his shirt, comes up and asks if she's okay. She rasps that she's sore and can't breathe. "That was…" Ruiz begins, and says, "We got him. It's over." All Cross says is, "Maybe." Ruiz follows her toward the all-purpose interview room as she says that Childress is insane. "I'm just not sure that the man who planned all this is insane." Ruiz reminds her that they have the bone saw, and the car. Not to mention Childress' book. "It's him." I'm actually with Cross on this one. Childress may well be The Beast who's been killing young women in Juarez, but I don't think he's the killer they've been after.
Personally, I think the killer set him up, like he did Ralph Gedman and Daniel Frye. There's just not enough that fits. And did you notice that when they were on the phone, Cross never mentioned Cristina Fuentes, or Judge Gates, or the poisoned immigrants, or Maria, or Gedman, or Peter or Gina Meadows? Sure, she ran out of time unexpectedly, but now Jack Childress is handcuffed to a chair in that interview room and she can ask him anything she wants. She cracks the door open. "Officer," he greets her without looking at her. Cross says that he could have run, and asks why he stuck around to shoot. That's just about the least illuminating question I can think of, under the circumstances.
Childress thinks on it a minute and says his job wasn't done. He looks at Ruiz standing behind her and says, "I meant to kill the Mexican." Does he mean he meant to kill Ruiz and Stokes, or Ruiz instead of Stokes? Instead of following up, Cross looks back at Ruiz, who raises his eyebrows at her all, "Well?" I have to admit that it was certainly an answer the killer would give. Especially if he wanted to lead the cops to Jack Childress. On the other hand, the real killer had an excellent chance to kill Ruiz once before and didn't, so there's that.