User blog comment:Christina.goddette/Multiplayer/@comment-4043223-20120310215825

Apparently you can do it in singleplayer but you need to do almost everything in the game, scanning, side quests etc, whether you chose to destroy the base affects your outcome too. If you saved it you get 110 less point or something like that. Plus you have to trick the Krogan into thinking there's a cure (from hat I hear).