FNAF Security Breach Ruin - Ruined - Multiple Kid Route/AU

Gregory (Freddy), Cassie (Roxanne), Morris (Montgomery), Aera (Chica) and Tayanita (Sun/Moon) decide to go to the Pizzaplex as a joke after it's been abandoned for a good 5 years now. They prepared and everything, but still somehow got split up in the abandoned building after hearing voices- voices of adults. Of course a group of teens will scatter at the sound of adults when in a place they aren't meant to be, but was that actually a real adult? Was it something evil trying to split up nearly defenseless teens?