Christopher Herrmann (David Eigenberg) is out of the woods, physically speaking, after his stabbing at the hands of Freddie (Ralph Rodriguez) on Chicago Fire, but he's still got a long way to go on the road to recovery.

"As a character, he kind of gets knocked back on his heels," Eigenberg tells "He's always trying to do the right thing and ... he miscalculated in this situation. He questions himself and kind of questions humanity, because the impulse was to help out and it slapped him in the face. So it kind of rocks his world a little bit. He's going to be fighting through a break in his confidence, and it's not really a normal place for him. ... It's the first time in his life he's really been knocked for a loop."

On the Set: Go behind-the-scenes of Chicago Fire

With the rest of the guys from 51 rallying around him - including Cruz (Joe Minoso), who, according to Eigenberg, continues to be "really, really messed up about" bringing Freddie into the firehouse in the first place - Herrmann doesn't waste any time in getting back to work. But the attack is never far from his mind, especially as he's faced with the decision of whether to bring legal action against Freddie.

"Sometimes revenge gets the best of all of us. It certainly grabs a hold of Hermann. He wants retribution, and he goes pretty hard at it," Eigenberg teases. "As it unfolds ... more pieces of the story are revealed to him. Some people in America come up in really crappy, crappy situations, and it affects their ability to make decisions. I think Herrmann understands that there are turning points in everybody's life where you come to a juncture and you realize you go left or you go right. ... He's gotta fight his own demons through it."

And Herrmann's near-death experience isn't the only thing that causes a shakeup for 51 in upcoming episodes. Namely, another "changing of the guard" is imminent, and will prove to be "disconcerting" for the crew.

"We have some changes coming up that are going to kind of make the house vulnerable again, seeing how people fit in or don't fit in," Eigenberg teases. "We always have our problems."

Watch Minoso's take on the Freddie/Herrmann story line here:

Chicago Fire airs Tuesdays at 10/9c on NBC.