Not sure how it works for KaRRiLLioN's missions, but I found the NearestObject command can be un-reliable when used with the fired event. It will not always detect the round in time, if there is a lot going on or the muzzle velocity is to high.
If your playing a MP game and team up with someone, they can direct your fire. But inevitably someone cries Cheat, as they cant see what the hell is firing at them
So an offical server version would be good.