His first and only thought when they burst into the apartment was that she was dead. Later, he would tell IAB that he wasn't sure, that he had seen Frankie pointing a gun at Detective Bonasera, his finger on the trigger. He would tell them that he had identified himself and then fired his weapon to protect a fellow officer.
But he had really thought she was dead. He knew he had yelled something, but he suspected it had been her name instead of 'police' or 'NYPD.' And he had fired his weapon for one thing only – vengeance. In his mind, he had seen his best friend dead and her killer standing over her, and his finger had pulled the trigger without a moment's hesitation.
As the others rushed into the room, he moved forward, his gun still trained on Frankie. His eyes kept threatening to slide over to Stella, but he forced them to stay on the man in front of him. He kicked the gun out of his reach and then felt for a pulse, a frightening satisfaction rising inside of him when there was nothing.
With Frankie down, though, he had nowhere else to look. Without even realizing it, his eyes looked up and around, searching her out, a painful knot forming in the pit of his stomach. Flack was kneeling over her, her face in his hands, and when he finally looked back at him, it wasn't with the look of sorrow he had been expecting.
"She's alive, Mac," he breathed, the disbelief in his voice telling him that he had made the same assumption. "She's alive."