If you still need to do your shindig in the crucible quest go to private matches with some friends and kill them without them killing you. If you kill ABOUT 2 guardians it will give you 1%. If you win a match with guardians in it, it will give you 3%. You can't solo it for the quest to advance. In my experience I learned it is easier to just go set up a rift match of Private Matches and put the score to 2500 points on the Thieves Den or The Anomaly (You do not have to set it to these maps but it is helpful). Do this over and over and you should have the quest done quickly. Bungie will patch this so hurry up.