[Warning: The following contains spoilers for Tuesday's fall finale of This Is Us. Read at your own risk!]

"Nothing bad happens on Christmas Eve," is the Pearson family holiday motto on This Is Us. Fans of this show knew that as soon as Rebecca (Mandy Moore) uttered those words they should prepare for the worst — and of course the episode left us with a potentially devastating cliffhanger to stew over until the show returns in 2017.

It wasn't little Kate that suffered though, or fan-favorite Dr. K (Gerald McRaney), who found himself as a patient in the hospital on Christmas Eve 1989 at the same the Pearsons were there for Kate's emergency appendectomy. The bad news came in the present storyline after Toby (Chris Sullivan) flew all the way to New Jersey to tell adult Kate (Chrissy Metz) that he couldn't live without her. At the end of the night's festivities, Toby collapsed in Randall's (Sterling K. Brown) living room and was rushed to the hospital. The closing moments of the episode showed Toby flatlining on the operating table with doctors attempting to revive him — and we'll have to wait several more weeks before we find out whether he survived.

Chrissy Metz, <em>This Is Us</em>Chrissy Metz, This Is Us

Since the first episode, Toby has been a shining part of Kate's storyline. He pushed her to be the best version of herself, even when his actions forced her to do that without him. He regressed on their diet and Kate had to make the tough call to look out for herself and not let anyone, including the man she loves, hold her back. That sort of strength was undoubtedly what inspired Toby to get back on the bandwagon because he knew they were better together than struggling alone.

Together is the important word here. For years, Kate was dependent on Kevin (Justin Hartley) as her confidant and best friend. Their lives revolved around each other and it took Toby showing up for either of them to realize that was unhealthy. Kate didn't allow her life to revolve around Toby instead, but they have become best friends and the people they confide in when things get rough. With Kevin living in New York now and Kate 3,000 miles away from the rest of her family, Toby is an essential part of her journey and his death could be a hard blow that Kate doesn't have the strength to handle at this juncture.

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Kate is already pushing herself as hard as she can to try to lose the weight she's gained over the years. She's even contemplating a life-threatening surgery to be able to drop the weight at a reasonable speed — but will she be able to stay on track if Toby isn't there to support her? Yes, Kate needed him on the diet as well for support but Toby's real gift is that he loves Kate as she is. That is an essential thing to have when combating her fear that she'll lose the weight and still be a version of herself that she doesn't like. Toby is there to remind Kate that she's worthy of being loved, which allows her to survive setbacks and roadblocks that may end up in her way.

The idea of Toby not making it won't just put a massive hole in Kate's storyline, it will add a sense of emptiness in the show as a whole. Toby carries a lot of the comedic relief weight (though Randall has been catching up recently), and just like he balances Kate, his sarcastic and dry sense of humor helps to balance some of the heavier drama of the show. If he doesn't survive the surgery, it's safe to say This Is Us would become a different show.

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The idea of losing Toby is also a reminder of how attached viewers have become to the Pearson family and those closest to them. We were able to deal with the loss of Jack (Milo Ventimiglia) because we still see him in flashbacks. If we are this upset at the idea of losing Toby, how much is it going to hurt when William (Ron Cephas Jones) also leaves us?

Are you ready to say goodbye to Toby?

This Is Us returns to NBC in 2017.