The police department is thrown into chaos when one of its own is targeted on this week's Chicago P.D.

After Sgt. Platt (Amy Morton) is attacked and severely injured while walking to her car, it shakes up everyone in the department — but particularly Burgess (Marina Squerciati).

"There's a lot of love, despite all the tension between them. ... [They're] best friends. I don't think Platt knows that Burgess is her best friend, but she is," Squerciati tells TVGuide.com. "When Burgess visits Platt in the hospital, it's a real role reversal. Platt's in a position of weakness and Burgess isn't. How does Platt handle that?"

TVGuide.com also chatted with Squerciati about Burgess' new partnership with Julie Tay (Li Jun Li), how long her vow of celibacy will last, and whether we'll see her move up to Intelligence this season. Here's what she had to say:

TVGuide.com: Burgess and Tay have now had a couple of run-ins with Tay's former boss, Commander Fogel (Ian Bedford). How is Tay's sexual harassment story line going to play out? Squerciati: I think the whole commander story is really going to surprise people. I think everyone assumes it's going to go a certain way, and I hesitate to even tease it, but it's going to really shock people, what happens.

After some initial awkwardness, Burgess and Tay seem to be getting along really well.
Squerciati: This world that we see is very male-dominated, and whenever you see two women together and they're not talking about boys all the time, [it's] great. ... I think what was cool about the [Burgess] and Tay storyline is that, I'm a little shy when I get to know people, and then I'm like an open book. But it takes me a few minutes to warm up. So it's kind of followed that trajectory. You don't really know someone, you're a little reluctant to meet them and open up. [Burgess] is like, "Why is she here? She's probably a bad cop." And then you realize, oh, OK, and just kind of open up and the friendship just kind of blossoms, onscreen and offscreen. So I think you'll see that rapport. We got to be really good friends. [Tay and Burgess' friendship] kind of blossoms in the same way.

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What kind of support do they provide for each other?
Squerciati: Tay is going to push Burgess to what she needs to do, either romantically or professionally. ... [Burgess'] head's kind of spinning. She's had a crazy year. She's been engaged. She had a partner, he was shot, he left. She's just trying to figure out what to do, where to stand. Taking a step back from not just men but from life a little bit is a good idea for her. And Tay is going to be the one to kind of nudge her in the right direction.

How long is Burgess' vow of celibacy going to last? Is there a chance she'll get back together with Ruzek?
Squerciati:
I don't know. I tried to ask the writers and they have not been forthcoming. They tell me that the Ruzek thing is not going to happen. But I kind of feel like it's like Chekhov. They introduce a gun in the first act, you know it's going to be used in the second act. Somebody takes a vow of celibacy, they're probably going to break it. That's television, right? I don't know with who, (Laughs). I feel like, three strikes you're out. I feel like [she's] got to go back to Ruzek. But I really don't know.

Does Burgess still harbor aspirations of moving up to Intelligence, and will we see that play out this season?
Squerciati:
I don't know. I feel like she's really been happy where she was, and Roman really made her appreciate the streets and where she was. If she does have those desires, I feel like they've definitely been pushed down. So, if they're going to come up, there has to be an impetus. There has to be something big to make that come up again, otherwise I don't think it will. So, we'll see!

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Speaking of something big ... do we see Burgess work with the Intelligence team at all after Platt is attacked?
Squerciati:
Burgess is asked to come upstairs to help with the investigation, and she's really singularly focused. I think when she's up there sometimes, she's worried, she's trying to impress Voight, she's trying to blend in with the group. And I think when it's her best frenemy - that's the best way I can [describe] Platt - she's just like, I've gotta solve this case. I've gotta help Platt. ... It's a really interesting episode, and it's good that I'm up with the team, because I don't think that Burgess could focus on anything else if Platt was in the hospital.

Can you tell us anything else about the assault on Platt?
Squerciati:
I don't know if everybody who watches our show knows this, but Amy is one of the premiere theatre actresses of our generation. Just a real powerhouse and just a really incredible woman. ... I think it's so great that she gets to spread her wings and really school all us CPD-ers, show us how it's done. ...It's funny, whenever Amy has a scene outside of the desk I'm always like, 'You have legs!' Because we never see them. I like to joke that it's always a surprise. Like, maybe she's wearing sweatpants underneath the desk. We don't know.

Is Platt's attack related to her argument with Commander Fogel at all?
Squerciati:
Platt's storyline has to do with something that hasn't really been introduced, but is kind of surprising.

Chicago P.D. airs Wednesdays at 10/9c on NBC.