The objective of this study was to analyze trainers’ activity during fire-fighting training for Belgian Sergeants. Specifically, we are interested in the trainers’ use of video in post-simulation debriefings. The results show that the trainer primarily stopped the video to point out candidates’ errors or remind them of the procedure. Furthermore, trainer mainly used expository pedagogical interventions to correct errors rather than promote learners’ reflection. Finally, he most discussed aspects of the sergeant’s job focused on command skills and safety management, which are specific tasks for the sergeant’s function, although these aspects were not always considered difficult by the learners.