'This Is Us': Will the Clinical Trial Work? Why It May Not Help Rebecca

Meaghan Darwish
This Is Us rebecca mandy moore
Spoiler Alert Ron Batzdorff/NBC

[Warning: The below contains MAJOR spoilers for Season 4, Episode 17 of This Is Us, "After the Fire."]

This Is Us may have delved into the "what if" question, but the end of Tuesday's episode, "After the Fire," viewers saw Randall (Sterling K. Brown) convince Rebecca (Mandy Moore) to partake in the clinical trial he tried selling her on in the prior installment.

Essentially guilting her into signing up, it appears that Rebecca will be transferring to Missouri for nine months to participate in an experimental trial that could improve her recent Alzheimer's diagnosis. But there's been a few flash forward hints that it probably won't be successful. Below, we're breaking them down.

Sibling Estrangement

This Is Us Rebecca Mandy Moore

(Credit: Ron Batzdorff/NBC)

Randall convincing Rebecca may be enough to cause a crack in the Big 3's relationship alone, but imagine if the trial is unsuccessful? Kevin (Justin Hartley) was adamant that he didn't want Rebecca participating in the trial, but agreed to let her make her own decision, and Kate (Chrissy Metz) was rather hands-off in the matter.

Why would they refuse to speak to Randall unless Rebecca's new "decision" didn't work and they lost valuable time with their mother who's memory is fading? Time is definitely the key here, and nine months from that point would see her return to the family around the time of the Big 3's birthday, leading to our next hint that this trial won't work.

Memory Issues Teased

This Is Us Rebecca Mandy Moore

(Credit: Will Hart/NBC)

In the midseason finale, which also saw the Pearsons celebrate Thanksgiving, it was revealed that Rebecca wandered off and got disoriented as she went to the grocery store, grabbed lunch at a Chinese restaurant, and proceeded to have a meltdown when she couldn't find her phone. While fans were under the guise that this was happening in the present timeline, it was later revealed that it was part of her future as police delivered her back at the Pearson cabin with Kevin, Kate, and Miguel (Jon Huertas).

It's clear that Rebecca's going to get worse and in under a year. If taking part in the trial is supposed to improve her symptoms, it doesn't seem to be working.

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She Doesn't Go

This Is Us Season 4 Rebecca

(Credit: Ron Batzdorff/NBC)

After being pressured by Randall, perhaps Rebecca will lean on Kevin and Kate for support, going back on her phone promise and distancing herself from the Philly-based son. Perhaps the fracture between the siblings isn't the result of her attending the trial, but instead her going back on her word and avoiding Randall in the process.

No matter the circumstances, viewers can anticipate seeing Rebecca's mental state getting worse in the future. They'll have to tune in and find out if the trial has anything to do with it.

This Is Us, Tuesdays, 9/8c, NBC