As Reece explains, the group expected a possible attempt of incarceration of their goals from corrupt powers running the world, as seen in Waco and Ruby Ridge affairs, and justified a possible mass suicide with the Biblical reference of the Jewish sect at Masada 73 A.D. standing their ground against the Roman siege, eventually taking their own lives (153-154).
The agents of ATF storming the compound of the Branch Davidians
The end result: The compound up in flames, resulting in 76 deaths