Simulation-based training for prehospital emergency care is characterized by high degrees of complexity. Thorough knowledge of both the work and the setting is crucial and it is therefore important to involve both end-users and other stakeholders during the whole design process. This paper investigates a design process by focusing on how project participants experience the work process and participation of a multi-disciplinary, research-practitioner design team. This case study focuses on the work within a development project of a new prehospital emergency training facility. Open-ended interviews were conducted with the project participants halfway through the project. Strikingly, the results show that while there are problems and tensions that potentially could overturn the project, all participants express strong satisfaction with their participation in the project. This implies that the accumulated positive experiences are so strong that they overshadow tensions and problems that under other circumstances could have caused a project breakdown.