A pendulum guarded the only exit to their prison. Large and heavy, oscillating so fast that it looked like a wall, it death masquerading as a fixture.
Once a month, the pendulum stopped.
First, it allowed for a change of the guards and other necessities to keep things moving. It was also when new victims were dragged in.
Second, the crew used the time to maintain the large device.
Third, it gave the captives a chance to escape.
It was both an opportunity and a trap.
If anyone made it out the entrance, they were free. Keyword: if. Once a month, while the pendulum hung still, everyone had their eyes on the empty space around the exit, guns ready for whoever dared to make the attempt.
People still tried anyway. Every few months or so, there were always those who willing to risk death for their freedom. No one had actually managed to be anything more than another red pool on the ground.
But that was because they didn’t plan ahead.
The challenge might only come once a month, but they had been preparing their escape for two years. Without giving themselves away, they gathered all the materials they could to create enough sleeping agent to drug all their captors, and carefully gained enough trust to have access to the kitchen. Thus, for the first time ever, the path out of captivity was completely clear.
Like a broken dam, they surged towards the entrance and out to freedom.