Because I tell them to! Yes, people will do violence to each other at my whim. Oh, the power. It's all in the name of art, of course. And sadism. I have convinced 6 people to play a game (which is a "performance art" thing)--they won't know the rules in advance and have agreed to follow whatever rules I set. So, that kinda makes me god. Oh, the POWER! I'm drunk on it.
They won't be using real guns--apparently that's illegal even down here--they'll be using paintball guns. But from what I hear, those things hurt pretty bad. There's more to it than the shooting though. The whole thing is going to be a ridiculous, over-the-top, all-too-brief extravaganza. I'll be sure to link to the video, when it's done.
In the meantime, here's a pic from Buenos Aires.