'Chicago PD' season 4 episode 5 spoilers: Mouse returning to army; Halstead believes he is being reckless

"Chicago P.D." season 4 episode 5 will be the episode where fans of Mouse (Samuel Hunt) will have to worry about the civilian tech surveillance expert.

In this episode, which is titled "A War Zone," Mouse will entertain the idea of re-enlisting in the army. He and Halstead (Jesse Lee Soffer) served as Army Rangers way back.

Speaking to Entertainment Weekly, "Chicago P.D." executive producer Matt Olmstead said that the former's decision will throw the latter into "a huge spin in terms of not thinking the guy's ready."

In a separate interview with TVGuide, Olmstead said that Halstead will be "adamant" in making his best friend stay in "Chicago P.D." season 4 episode 5, but his reasons are more about him than Mouse.

"Is it out of concern for him, does he not think he's equipped to go back and do it, is it his own fears or anxieties or scars that he carries with him that he's attributing to Mouse?" Olmstead told EW.

"We're playing that over a couple episodes—this friendship, driving a wedge because he doesn't want to facilitate Mouse going back over there to serve because by doing so, am I signing this kid's death warrant?" the EP continued.

Halstead believes that Mouse is being reckless and if he lets him go through his plan in "Chicago P.D." season 4 episode 5.

As fans know, Halstead was the one who basically helped Mouse to get back on his feet after a struggling phase in his life. He believes that if he returns to the army, his efforts and Mouse's progress will all be in vain.

It is unknown at the moment if Halstead will be able to convince Mouse to say. "Chicago P.D." season 4 spoilers suggest that he could end up being a key member of the team.

It is being said that he could fill in for Detective Antonio Dawson (Jon Seda), who will be out of the group soon and into "Chicago Justice."

"Chicago P.D." season 4 episode 5 "A War Zone" airs Wednesday, Oct. 26, at 10 p.m. ET on NBC.