I agree with a lot of what Ph8te was saying. I was surprised Katie was so brutally honest with Lily. She was trying to explain why Sergi had
to be killed, and why they didn't feel any remorse about it. There was really no other choice. This technology simply cannot
be allowed to get out in the wild, especially to the Russians. It could end the world as we know it. Perhaps that is what Sergi saw, what terrified him so much. Or maybe he just saw Lily's death...?
Katie knows they are playing with fire at Devs, and she might feel like if she can get close enough to Forest, including being his "girlfriend", she can reign him in, maybe convince him not to do what he seems determined to do. Which is, as we've probably figured out, change the timeline to bring his wife & daughter back. That's why he's uninterested in the multiverse. He can only exist in this one.
She knows something terrible is going to happen 21 hours from now. The timeline will no longer be predictable. Determinism will fail. My guess is Lily ends up at Devs and somehow fraks with the Machinery. Ends up killing her, or perhaps she is killed by somebody else (probably not Kenton) in order to prevent her from breaking or changing the machine. Note that Katie did not
tell Lily she was going to die, just that their ability to see the future, made by specific decisions, ends at that point.
So, perhaps genuine randomness is thus introduced into the equation at that point? If so, it is/was likely something Lily will do.
I agree Pete is more than he appears. Otherwise, what's the reason for him to be in the plotline?
It's not just Lily that's a wildcard, either. Lyndon is back, and he's going to get Stewart to help him get back into Devs. Gotta' love Stewart. He's probably a millionaire yet he prefers to live in a run-down RV. These Amaya folks are sure not pretentious.
Fun fact: Notice the name of the young actress who plays Amaya (IMDB is your friend). Interesting. I actually noticed it in the end credits last night. I'm one of those weirdos who watches those things.