Go on Xbox Live and go on matchmaking, or with as many friends as possible, and go on the Isolation map. Change the game mode to team slayer.

When you begin go next to the giant wheel on the ledge where the blue team usually go and pick up the sniper.

Crouch down and start shooting enemies. Get 2 other players (1 on 1 side and 1 on the other side) then no enemies can get to you.

Usually your players will respawn here so your players will never run out if they die and you are protected!