Wayward Pines is just full of surprises.

Nurse Pam (Melissa Leo) popped back into the story, and she brought a few of Pines' OG cast with her. Pitcher's sister took viewers on a trip down memory lane, revealing exactly why her son Jason (WHAT!) is so cracked in the head. As it turns out, crazy runs in the family.

Dismayed by the state of her brother's dream town, Pam spent "Once Upon a Time in Wayward Pines" attempting to undo Jason's fascist regime. Her weapon of choice? Bioterrorism. Dosing herself with a vial of smallpox, the medical professional set out to break her Hippocratic oath.

In the end, Megan's (Hope Davis) meddling led the season 1 heroine to be strangled by her son's hand.

Leo discussed her finally scene - and outfit - in the wake of the Wednesday episode.

"To step back into a character that I had grown very attached to over several months, really, inventing her with the writers a few years ago, to go back and find my way into her was serious business for this overly serious actor," Leo told Entertainment Weekly.

The red dress, meanwhile, stemmed from the character's tendency to costume her self for each mission.

"The original costume designer and I had realized that Pam costumes herself, and the nurse's costume, although she's a nurse, is a costume. And so is her military garb, and so are the many guises she puts on to go and collect people," Leo explained. "So I'm seeing this as her getting dressed for this Typhoid Mary role."

So you think Leo's parting words to her son will change the course of Wayward Pines, or will Jason's (Tom Stevens) schooling outweigh his mother's wisdom? Find out when Wayward Pines airs Wednesdays at 10 p.m. ET on Fox.

Click the video below to see a preview for the series' next episode, "Exit Strategy."