As teachers shift their practice from traditional student-to-teacher interaction patterns to collaborative discussions around rich mathematics, they often encounter instructional challenges. One such challenge is deciding when to pursue interesting and productive ideas that run contrary to the particular mathematical goal of the lesson. In this research summary, I report results from a study involving one experienced teacher's instructional decisions and how she maintained attention to the lesson-specific content goal given possible alternative pathways. [For the complete proceedings, see ED606556.]