The prime objective of House 51 is to put out fires and save lives. However, in between all that sacrifice, the members of the Chicago Fire Department must live their own. On Chicago Fire, that has not been a problem. While the cast is large, the writers have managed to carve out a lane for each person. Just another example of the genius of Dick Wolfe.

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After seven seasons and countless episodes, what are some of the details that we've missed? Writers are good to place some right in front of us and see if we catch them but some are so tiny that they slip by the most loyal of fans. Here are the 11 hidden details about the main characters everyone missed from Chicago Fire.

Matt Casey

Matt Casey riding on the firetruck.

When someone has something they love, it's safe to say it becomes their favorite. Can you remember your first car or the first person you fell in love with? Those tend to stick out as favorites. But for Matt Casey, he took his most prized possession with him for four years. Fans were so intrigued by his character that this small detail may have been missed.

For the first four years of Chicago Fire, Matt Casey, every time shown outside in the Chicago winter would have on a waist-length navy blue coat. Maybe it had some sentimental value to it but it sure seemed to be the only piece of winter clothing he owned. Once again, a detail so small that you will have to go back and see it for yourself.

Kelly Severide

Severide in Chicago Fire

In Season 2 of Chicago Fire, there was a slight change for Kelly Severide. Nothing to do with his hair, his apartment or the way he walked. What changed about Severide was so subtle that most fans had no clue it had gone down. In the first season, his badge number was 1751. However, by the start of Season 2, Severide had a new badge number - 1068.

What was the meaning behind the change? Did it really matter all? Did it have to be a meaning? Was it a mistake by the casting crew? It changed nothing about Kelly as he's continued to do his job. Just something so small that the naked eye may have missed that detail.

Joe Cruz

Cruz in Chicago Fire

Firefighters and Police Officers often find themselves in some pretty tight situations. In more than a few occasions, House 51 has been in pretty nasty conditions were fights, gunshots and other violent acts have taken place. During these times either Boden, Casey or Severide have taken action. But why haven't the writers let one of the biggest Smoke Eaters throw his height and weight around?

Cruz is from one of the roughest parts of Chicago and yet, he has the gentle's heart in House 51. Take Kevin Atwater from Chicago PD. He's from a tough area and walks around ready to knock someone out. Not saying Cruz runs from fights but if there is to be a watch guard for House 51, why not the use his size and brawn?

Wallace Boden

Wallace Boden standing in front of a burning truck in Chicago Fire

Boden will talk about the good ole days with Benny Severide or Henry Mills but rarely does he talk about his life before joining the Fire Department. Trying to discover Wallace Boden's thoughts could be like trying to break into Fort Knox. You know there's gold in there but is it really worth all the hassle?

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Being a former member of the Navy Seals would explain why Boden is so tough on the outside, As the leader, he has to show a certain level of discipline. He can still be a shoulder to lean on but for the most part, his actions scream of distance. How often does Boden go to Molly's to hang out with the guys? How often does Boden climb on the roof of the Firehouse to smoke a cigar with Casey and Kelly? We can't help but ponder.

Sylvie Brett

Sylvie talking to someone in Chicago Fire

Sylvie has been through four paramedics since she became a member of House 51. With so much onus on Gabby and Shay, its Sylvie who has been through the most partners on Ambulance 61. Starting off, she paired with Gabby, then went with Jessica Chilton before Jimmy Borrelli. After that, she went back to Gabby before finally settling on her present partner Emily Foster.

While Shay was no-nonsense and Gabby was a bit of a rebel, Sylvie is all heart. She has her moments of strength and weakness but she's great at what she does. But in her time with House 51, she has seen the most turnover. She's strong and one of the reasons, she's a fan favorite.

Gabby Dawson

gabby thinking in Chicago Fire

When Molly's opened, Gabby was a co-owner along with Herrmann and Otis. However, with Gabby off to Puerto Rico, did she give up her part of the bar or does she still have input? It was never mentioned in Season 7 what happened to her percentage of Molly's.

If she's still involved in Molly's then it's not fair for her partners to be there for the everyday needs while she collects a check. I know it won't be addressed in Season 8 but that's a small detail that was left out last season.

Randy McHolland (Mouch)

Mouch looking at someone with a serious expression in Chicago Fire

In Season 3, Randy (Mouch) learns that he has a daughter. While that's not the strange part, the weird thing is, she vanished just as quickly as she came into the storyline. Where is Lizzie and why hasn't she come back into her father's life? For a show built on family and honesty, she would fit right in and give us more of an insight into Mouch as a man.

One episode was all we were given and that wasn't fair. Mouch has a daughter but yet, we get to see Herrmann's kids, Casey and Gabby fight for adoption, Boden and his family, so what makes Mouch, Trudy, and Lizzie so different?

Christopher Herrmann

What doesn't Christopher Hermann have his hands in? For starters, he's a Fireman, owns a bar, coaches his kid's hockey games, and is willing to knock on people's doors to check up ok them. But how many times in the past seven seasons have we actually spent inside his home with his wife Cindy?

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When dealing with the big and diverse cast of House 51, there tends to be some sort of home life we've become accustomed to, especially when it comes to personal relationships. However, for Herrmann, we don't get that. There has to be some kind of romance there as they share five kids but his quiet time with his wife has never been mentioned.

Brian Zvonecek (Otis)

Otis laughing in Firehouse 51 of Chicago Fire

Ever wonder why he's called "Otis" when Brian is of Russian descent? Many fans assumed it was his middle name but that's not the case. The story is that while a candidate, Brian was named the elevator specialist of House 51. That's important as most elevators are made by the "Otis Company", hence the name Otis.

What's even more intriguing to see is that when he introduces himself to people he uses Brian and never Otis. It makes you wonder if he's comfortable with the name, yet the Firefighters inside of House 51 rarely call him Brian. We know Otis can be a bit sensitive but he seems to take the joke in his stride.

Stella Kidd

Stella Kidd looking curious in Chicago Fire

Ever wondered why in most romantic scenes in TV or movies, men have to almost always bend down to kiss their leading ladies? Well, for Severide and Stella, that's not a problem. Standing at 5' 11', Severide has no such issue when he goes in to kiss the 5' 10' Stella Kidd. According to her height, that makes Stella the third tallest main character on Chicago Fire.

You can see the size difference when Boden or Cruz are on-screen but know that these men who run into buildings to save lives, some are shorter than Kidd.

Emily Foster

What's the one thing that the women in House 51 have in common? You give up? They all have at some point in time, dated one another, except Emily Foster. Although she's new, Emily has had time to pick and choose. Casey is single. At one time so was Severide, Otis, Joe, and even Stella and Sylvie. So why is Emily different?

With so many hookups going on in House 51, maybe the writers decided to go a different route. Think about it. Sylvie and Joe, Stella and Severide, and Matt and Gabby. Emily could just be playing it safe and smart and not wanting work to get in the way of pleasure.

NEXT: Chicago PD: 10 Hidden Details About The Main Characters Everyone Missed