Armstrong, the Strong Arm Alchemist, arrives just as things are looking bleak for Ed, Al and Marcoh.  He is able to occupy Scar so that Ed and Al can escape with the doctor.  Armstrong realizes that Scar is from Ishbal.  Marcoh tells Ed and Al about the Ishbal 'Rebellion', or what he calls a massacre.  He and other State Alchemists were ordered to destroy the entire city using Red Stones.  These actions caused Marcoh to defect and still lingers with Roy Mustang and Armstrong.  Scar meets up again with Ed and Al, severely criples them before having to escape through the sewers.