WARNING: If you don't want to know what happened in this episode, don't read this photo recap!
Operation Bitemark has made their way to Washington, DC. Their final stop on this particular trail, Roberta Warren needs to find a way into the secret bunker that holds what she's been looking for: the Fourth Strike weapon called "Black Rainbow."
What the team finds, of course, is a place full of zombies who were trained to kill kill kill. (Really. There's even a sign that says that.) Also in this bunker? That spooky old man from Zona. He's been trying to make Black Rainbow happen all along.
And then…twist! A flashback reveals where Roberta's visions have been coming from all season. It turns out that while she was in that coma, Dr. Teller woke her up and gave her all kinds of training to defeat the zombie-apocalypse.
All the visions she's had throughout have been the result of her training. The canisters, how to put them where they need to go, where she was headed all along - it was all implanted in her brain by Doctor Teller. The canisters are the cure for the virus! To be spread worldwide!
In flashback, Doctor Teller shows Warren the canisters. She's been collecting them and imagining them all along, and now the time has come to load them into the drone and send them on their way to cure everyone.
And that's when Roberta remembers the truth. That while Dr. Teller told her that she was the answer to everyone's prayers, all that training had been so that she could deliver the reset, the Black Rainbow, and set every living thing in the world on fire.