Sunshine knew about Warren and Murphy, as they were on the same flight out (and he was Teller's assistant in deleted scenes). He looks in their direction as they walk away from the Zona vehicles in 'Escape From Zona', but doesn't try to stop them.
AfterBuzzTV:
According to Karl & Abram, Teller has always been evil & was 100% Team Zona. Sunshine is one of the few unvaxxed Zona residents, for whatever reason, and wanted to stop the Reset after discovering what Teller's fromula would do. The Founder tells Warren that they've met 'many times' before, so I think her training took up most of the 2yrs, with Teller using repetition to imbed her mission so deeply within her mind.
I still have many questions, and I hope season 5 is less confusing!