'Blindspot' Sneak Peek: Is Jane Knocking on Death's Door? See the Emotional 'Jeller' Moment (Exclusive)

ET exclusively debuts a heartbreaking first look from Friday's episode.

Could Jane be knocking on death's door? 

On Friday's Blindspot, titled "The Tale of the Book of Secrets," Patterson (Ashley Johnson) and Rich (Ennis Esmer) jet off to Peru on a dangerous treasure hunt to help save Jane's (Jaimie Alexander) life, but could they be too late? Jane's condition has been worsening quicker than the team can fathom following her ZIP poisoning -- so bad that Weller (Sullivan Stapleton) isn't taking any chances when it comes to being by her side.  

"This is so unfair," a defeated Jane, confined to a hospital bed, confesses to Weller in ET's emotional exclusive sneak peek. "I thought we were going to grow old together."

"And we will," Weller insists, possibly trying to convince himself too.

"You don't know that. That's why you stayed behind," Jane says. "You've never turned down a field assignment in your life. You wanted to be here in case I die." 

Hearing Jane say those devastating words prompts Weller to reassure her that he doesn't believe that for a second. Considering that she's already lost her eyesight, it's getting harder for her to move and even more difficult for her to breathe due to the aftereffects of ZIP poisoning, it doesn't bode well. 

"I want to be here because I'm your husband first and my agent second," Weller says in the heartbreaking scene. "We will find those stem cells and we will cure you. I promise."

"My body's forgetting how to do everything," Jane says, breaking down, as Weller's eyes well up with tears. "I'm scared, Kurt." 

Even if Jane does survive this and is cured, any traumatic experience of this level will more than likely change her for good. We're crossing our fingers and toes that everything will be A-OK for Jane and Weller. 

Blindspot airs Fridays at 8 p.m. ET/PT on NBC.