adam ruzak

Chicago P.D's Patrick John Flueger explains that surprise ending with Kim Burgess 

Adam Ruzek and Kim Burgess remain close

Rebecca Lewis

Chicago P.D. returned to screens on Wednesday and fans were shocked to see Officer Adam Ruzek close the door in his ex-fiance Kim Burgess' face.

The pair remain close but Patrick John Flueger has now explained that Adam has always seen Kim as his "rock" and that was why he acted the way viewers saw.

Kim had knocked on Adam's door and asked him "what did you do?" after Adam shot gang leader Lucas to save his father, beat cop Bob, who had borrowed money to cover a gambling debt.

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WATCH: One Chicago airs on Wednesday's NBC

However her question, an accusation, left Adam feeling "alone," says Patrick.

"She could’ve asked, ‘What happened?’ But ‘What did you do?’ is an accusation and to have his bedrock make that kind of accusation towards him, it’s too much to bear with everything else that’s going on," he told TV Insider.

kim and adam pd

Kim and Adam ended their engagement but remained close

Adam's decision to save his father from gang violence - and allowing him to retire with his pension in tact - has put even more strain on their relationship though.

The pair were seen arguing in the hospital after, and Bob once again claims Adam may be ruining their family name.

Patrick added to the publication that during filming the pair used a lot of ad-libs, and that it was a "blast to shoot because they let us go free."

"We got a camera crew that’ll just follow you anywhere," he shared.

chicago pd-ruzak

Adam had saved his father from a local gang member

The One Chicago franchise airs on NBC, and launched in 2012 with Chicago Fire.

Chicago P.D. came next and the franchise now also includes Chicago Med.

Launched by Dick Wolf - the man behind the Law & Order franchise - it follows the professional and private lives of the firefighters, police officers, emergency medical personnel, and legal professionals who serve the city of Chicago.

Chicago Fire stars Taylor Kinney and former Neighbours star Jesse Spencer, while Flueger is joined by Jason Beghe and Jesse Lee Soffer in P.D. Nick Gehlfuss and Yaya DaCosta lead Med.

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