During the mission "Three Way" (which is replayable, so no need to worry about saving beforehand) you'll be presented with a choice: Chase down and fight Killbane or go save Shaundi. To get 'Too Close to the Son', you'll have to sacrifice Shaundi's life and hunt down Killbane. First you'll need to rescue Angel from STAG's forces, then he'll drive you to the airport while you keep everyone off your tail. When you get there, prepare to shoot down Killbane's plane (remember to aim in front of the plane and you'll have better luck landing shots.) He'll pop out, trigger a quicktime event, and you win. Enjoy the achievement and bask in the shame of what you gave up to complete your vengeance.
