It's a mode wherein bots run around in 120 mobility. The bots themselves are harmless, but the only way to kill them is a headshot. Your only weapon is a SWAT Rifle. If you fail to shoot the head, miss the target, or hit the body, you die. After dying, the whole map resets and you get to do it over and over again. You can also add achievements, which will in return award you with Gems.