Prior research has shown that including errors in training may result in improved retention of knowledge and skills. In this study, first-year anesthesia residents participated in a simulation involving hyperkalemia management. Half received support from an attending physician while the other half participated in the scenario independently. The groups were further split so that half of those practicing independently and half of those working with an attending experienced simulated mortality of the patient. The residents participated in another hyperkalemia simulation 6 months later without attending assistance. Residents who had practiced independently and experienced simulated mortality in the initial hyperkalemia scenario achieved the lowest mortality rate compared to the other groups during the follow-up simulation activity.