Chicago Fire is gearing up for the biggest episode of season 13 thus far. The way the episode "Post Mortem" has been hyped by actors and producers, you'd think it was a season finale. A character will be caught in the rubble of a collapsed building, and may very well die as a result of their injuries.
To make matters even worse, Wallace Boden (Eamonn Walker) is coming in to investigate what went wrong, and all signs point to the former 51 Chief firing whoever he deems responsible for the tragedy. That's potentially two Chicago Fire characters gone in the span of a single episode. Naturally, we have some thoughts.
We don't know who will end up going down in "Post Mortem," but these are the most likely candidates based on the context of season 13.
Christopher Herrmann

We're a bit conflicted on this one. Christopher Herrmann (David Eigenberg) definitely fits the bill when it comes to being a fan "favorite" character, which is who Eamonn Walker said was at risk. We've also seen the promo photos for the "Post Mortem" episode, in which Herrmann can be seen alone in what looks to be a deadly blaze.
Herrmann is getting older, and has suffered notable injuries in the job, like when his hearing was damaged in the season 12 premiere. The promo photos make it difficult to dismiss the potential of him being one of the casualties of the show, but we hope we're wrong.
Tony Ferraris

Hear us out. Tony (Anthony Ferraris) is a beloved presence in Firehouse 51, so he checks the box we previously alluded to about the victimized firefighter being a "favorite." He's also someone that, to be frank, is less essential to Chicago Fire cast than Herrmann or, say, Kelly Severide (Taylor Kinney).
Tony has been present for all but one episode of season 13, and he's proven himself to be a brave and durable firefighter in the field. This could represent an instance in which his luck runs out. We don't want anybody to go home in a body bag, but we have seen instances of Chicago Fire making huge deals out of deaths or injuries that wound up being tied to minor instead of major characters.
Dom Pascal

Dom Pascal (Dermot Mulroney) has the biggest target on his back when it comes to who could potentially get fired. The current 51 chief has exhibited erratic behavior on the job since his wife Monica (KaDee Strickland) died, which is not going to look good if he was at all responsible for the injuries his firefighter sustained.
It feels like the clock is ticking on Pascal's tenure, and while we have grown attached to the character over the course of season 13, we do have to confront the very real possibility that he will not lead 51 into the future.
Sam Carver

Sam Carver (Jake Lockett) is a beloved character who could, theoretically, lead Chicago Fire into the future. We've talked at length on this site about how Carver serves as a successor to Severide in a lot of ways, and we cannot overstate the value of this role as the show progresses. But we also know that the character has been dealt one crippling setback after another in season 13.
We could easily see a world in which Carver is injured in the line of duty, and is forced to fight for his life as a result of a building collapse. Chicago Fire showrunner Andrea Newman did say that Carver's return would be accompanied by a "surprise." Well, near-death would definitely be surprising.