Warning! The following contains spoilers for the latest episode of This Is Us. Read at your own risk!
This Is Us fans know Jack's death is coming before the end of Season 2, and the show just dropped another big clue regarding the circumstances behind it. Jack and Rebecca took a trip to the mall with the children, and while Jack managed to accomplish quite a few things, he did forget one important task. Jack forgot to remind Rebecca they needed batteries, which will eventually come back to bite him. The final shot of the episode revealed that the batteries were needed for the smoke detector.
As every This Is Us fan knew the moment they saw it, that smoke detector without batteries will be of no help when a fire eventually burns down the Pearson household. What fans might have just learned, however, is that someone was definitely in the house who may have benefited from a working fire alarm. The current assumption would be that it's Jack, although it's always possible he might have run into the burning home to save Rebecca or somebody else.
The broken smoke detector is a small revelation, but it also rules out a couple scenarios that have floated around the web with regard to how Jack died. As previously mentioned, the importance of the alarm being broken means that there is someone in the home who would've benefitted from hearing it when the fire started. If Jack rushed into the flames to save someone or something, it may have been for the sake of somebody who didn't recognize danger due to the lack of a smoke detector.
Smoke detector speculation aside, This Is Us definitely teased that Jack's death is just around the corner. If only Jack had remembered the batteries, this whole thing might have been avoided! Instead, Jack was hanging with Miguel, imparting life lessons onto his sons in a mall food court, and buying Kevin a suit he'll likely wear to his father's funeral any day now. The suit-buying scene was a simultaneously heartwarming and heartbreaking moment for fans to witness as they know what's coming, and probably the first of many "final memories" Jack will share with his children as his death draws near.
This Is Us is all new on NBC Tuesday, January 23 at 9:00 p.m. ET. For more on Jack's death, check out this article. It was big news when Sterling K. Brown swore fans will see Jack die before Season 2 concludes. For a look at some shows that are set to premiere or return to television in the coming weeks, be sure to visit our midseason premiere guide. If you're in the mood to rewatch some (or all) of This Is Us, the full series so far is currently available streaming on Hulu.