It's probably been pointed out already, but you were only capable of getting so many kills/points in the first place because your teammates were, quite clearly, exceptionally bad. Therefore you had little to no competition for kills while being able to simultaneously use them as fodder. If you're scoring more than 7000 points in a game, then your team is exceptionally bad and there was no hope from the get-go. There's a reason teams filled with good players typically score in the 4-5k range, with 20-25 kills each; there's simply too much competition between themselves for it to be otherwise.