Storyline:
Teresa and Betty (who are siblings in this AU and ARE WITH WCKD) met each other again 00:00 on the street, after a argument that Betty kept taking medications she didn’t need to. That’s why Betty became over and over aggressive towards her sister.
00:42 Then appeared a flashback, that Betty betrayed Teresa, as Thomas and the others had liberated her from WCKD back then, and she knew where she was. And Betty couldn’t forgive herself for that.
00:55 The weeks and months with WCKD the both had barely contact, as Teresa was mainly used to find a cure. Betty’s bad conscience haunted her terribly. And Teresa couldn’t understand that.
1:10 It was a secret, but Teresa got blackmailed by Janson, to get her sister to him, (that’s why she had to let kidnap Betty from their home) as lever so Teresa focus on finding a cure and not to refuse, as she doesn’t agree with their methods.
1:38 after Teresa saved Betty, both had separate, Teresa wanted to distract Janson so her sister could leave. But when Betty heard the shots she had to follow her.
1:47 Janson found Teresa and was ready to kill her, Betty came and needed to watch how Janson shot Teresa in her leg. What didn’t kill her first. Betty grabbed the Gun she found on the way to the laboratory and killed Ratman.
2:01 Thomas arrived in the hospital, after Betty called him. He was with Teresa in her last minutes, she died at the late effects..
Teresa has sacrificed her life for her sister, because she was (as her true character is) selfless, brave and protective towards the people she cared for the most. Teresa’s death showed Betty that she has forgiven her ( that’s why she smiled :) )