Lily arrives at DEVS. Forest is there to greet her. He explains DEVS to her, and the magnitude of what they've accomplished.

Forest explains that this computer version of Amaya is just like the real one. They're both going through fixed motions. Forest and Lily have a conversation that he's seen many times before, and they perfectly follow script.

Lily asks to be shown the footage of what she's going to do that causes the end of DEVS.

She watches herself shoot Forest while Katie and Stewart watch. This breaks the vacuum seal of the compound and leads to her death. The system can only predict up to that moment.

Forest explains to her that the name of DEVS is actually "DEUS", meaning deity or god.

The time has come. Forest, Katie, and Lily originally follow the script of what they're supposed to do exactly. But, Lily proves that their actions can change, when she throws the gun instead of shooting Forest.

However, Stewart still activates the emergency protocol and Forest and Lily fall to their deaths.

Forest appears to Katie in the visualization chamber. Katie explains that all of this only makes sense based on Lyndon's principle. 

Lily making a choice has stopped the system from working as they expected.

Lily wakes up back at the first day of the series. Sergei is alive.

Forest tells Lily they're in the system. DEVS, or DEUS is a pseudo-afterlife, taking them back to life a few days before Sergei's death. Katie resurrected them with their memories intact. 

He explains that they're living in many worlds at once. They lucked out, landing in one of the good ones. He tells Lily to follow her own path, because that's what makes her special.

Katie continues to run DEVS in the original reality.

Lily visits Jamie in the system. He doesn't know the difference between it and reality.