Have you ever noticed how Crucible matches end (seemingly) randomly in the last 5 minutes? As you just win, or lose? My theory is that if you are on a win/lose streak, and that Bungie have put you all together in the team, and they've already decided when the right time to call it is. That way if you suck or ace in your last few matches, you'll soon have a change of fortune. Match-rigging basically!