This article is about collaborative learning with educational computer-assisted simulation (ECAS) in health care education. Previous research on training with a radiological virtual reality simulator has indicated positive effects on learning when compared to a more conventional alternative. Drawing upon the field of Computer-Supported Collaborative Learning, we investigate collaborative patterns, their causes, and their implications for learning. We investigate why the extent of application of subject-specific terminology differs between simulation training and more conventional training. We also investigate how the student-simulator interaction affordances produce collaborative patterns and impact learning. Proficiency tests before and after training, observations during training, and interviews after training constitute the empirical foundation. Thirty-six dentistry students volunteered for participation. The results showed that not only the task but also the medium of feedback impacts the application of subject-specific terminology. However, no relation to proficiency development was revealed. We identified turn-taking as well as dominance patterns of student-simulator interaction but again found no relation to proficiency development. Further research may give us deeper insights into if and how these collaborative patterns, in other respects, impact collaborative learning with ECAS in health care education.