Just My Shitty Luck...
Sal phones you, and he says that he was spying in Fort Staunton and the Forellis and Sindaccos started a turf war with him caught in the firing line, and you need to get him out of there.
Saving His Ass Again
First, get the BP Limo from the Multistorey Car Park before heading over there. Get out, shoot up every Forelli and Sindacco in your way, get Sal back out and drop him off inside a garage near to your safehouse's garage.