This one is a little dark but there is a silver lining, so indulge me. I'm particularly interested in Juras answer, I think he knows the answer, and there is an answer, you'll understand when I explain it, but I'd encourage anyone with an idea to share it.
Here is the scenario.
You and one other person are tasked with watching over one hundred people in an open space, when one of you sleeps the other is standing guard. You have to make sure none of them escape. There are no fences or barricades to keep them inside, you have one gun and one bullet. The prisoners know that you only have one bullet. You have access to other items, but you cant build a prison, you can't tie them up or restrain them in any way, and you cant buy more bullets.
How do you ensure no one escapes?
Remember there are no wrong answers, if you think you have an idea please share it, once we've talked about it a bit either myself or Jura will tell you the answer.