Brennan had stayed where she was stood, turning around to look for Booth. Apparently they were both there but she'd apparently missed him, and Brennan didn't miss things. She heard his call and turned again, walking towards the sound of where the voice was coming from, calling back; "Booth?"
Brennan found it easy to ignore everyone around her when they turned, pushing through a small crowd of people in her search, a little smile appearing when she saw him. "Booth!" She was glad to see him; comforted by his presence and relieved that she wasn't in this alone - if she had been... Being kidnapped wasn't a situation that she'd wish on Booth, but he had the smarts that she didn't to help them in this.