The End Timers

Is Tammy losing her mind or is she uncovering a dark conspiracy?
In this sci-fi/horror/ thriller, doomsday prepper Tamara Umbra just bought a membership into a luxury fallout shelter called The End Timers. During a weekend visit to the shelter, an incident occurs, trapping her and her fellow members inside. Not able to take her medication, she hears a voice in her head. At first, she attempts to fit in with the others and ignore the voice. But the voice continues. It tells her that there is a conspiracy at work against her and everyone at the shelter is a part of it. It tells her to kill. Tammy struggles to decide if the evidence that the voice is showing her is real or imagined. Is Tammy the victim of a conspiracy, or is she just becoming a deranged mass murderer?