Over 5000 win points in Ranked matches.
If you have a 4 person boosting party still willing to play this game, this achievement is still attainable, quite easily with a glitch.
Taken from x360a.org:
http://www.xbox360achievements.org/game/quake-4/guide/Here is the easiest way to do it, and if done properly, you can get all four point achievements in one game. *Credit goes to Sina117 for this* Start an Endurance Arena CTF game. You will want to be on a team with 3 people and search for a game. Have a fourth person search as well. When the game starts, hopefully you will get a map with a pit. If there is a map with a pit, continue to part A. If not, part B.
Part A - So you're on a map with a pit. Congrats, this will be very easy. The two members of your team will need to kill themselves by jumping into the pit 100 times. They can not get a kill, touch a flag, anything. This should take about 10-15 minutes. After they kill themselves to -100, they are to sit there and not do anything, as though the slightest point could screw it up. The person that is getting the points, obviously the one not killing himself, will capture the flag 9 times with doubler. This should take about 4-5 minutes, depending on the map. Now, the lone person on the other team will (after nine captures have been made) take your flag (being your team) back to his base, BUT DO NOT SCORE IT! The lone person with the flag will get as close as possible to the flag, and when he does, the person receiving all the points (On the team of 3) will kill him, thus getting a holy sh!t everytime, which is worth 3 points. You will continue killing him until your point total is at 195 points, not kills, points. 195 points is what you need to be at. By the time you achieve 195 points, capture the flag, and return it to the base. But do not do so until your team has killed themselves 100 times. You will return the flag, your score will be 201, and you will receive 6k points for one game, which should take about 15-20 minutes, depending on how fast your team can kill themselves.
Part B - So, you're on a map with no pit? Well, you have two options. You can leave the game and keep trying, or take the other route. The two people on your team must still kill themselves to -100, however its a bit trickier. The easiest way to do it is to have them take the doubler, use a hyperblaster and shoot into a wall 100 times. Everytime they die the hyperblaster will drop in the same place, they can pick it up, kill themselves, repeat. This works with Nailguns, Rockets, etc. Just has to be done as quickly as possible. This may take longer, but it can still be done, it will just take about 15-20 minutes. Now, the lone person on the other team will (after nine captures have been made) take your flag (being your team) back to his base, BUT DO NOT SCORE IT! The lone person with the flag will get as close as possible to the flag, and when he does, the person receiving all the points (On the team of 3) will kill him, thus getting a holy sh!t everytime, which is worth 3 points. You will continue killing him until your point total is at 195 points, not kills, points. 195 points is what you need to be at. By the time you achieve 195 points, capture the flag, and return it to the base. But do not do so until your team has killed themselves 100 times. You will return the flag, your score will be 201, and you will receive 6k points for one game, which should take about 20-25 minutes, depending on how fast your team can kill themselves.