While playing Co-op mode with a friend, have him stand to the left side of the pipes just ahead of where you are and take cover. Have him shoot RAAM to get his attention. When Dom goes down and RAAM starts to come after you, he will be moving towards Dom. If done correctly, he should get stuck on Dom and not be able to move or send his Kryll out to attack you. You can now defeat him easily and earn the "Dish Best Served Cold" achievement. This is very difficult to execute and should not be attempted in Single Player mode.