The experience is still very intense. So it takes a lot of skill to debrief a group. It has to be done in a very non-threatening way. Covert says it's a crucial part of the training process, however. That's another important skill in dealing with critical events.
People always tend to want to hide their mistakes.
But if you make a mistake, you have to be able to recover from it. That's not done very well educationally in medicine. Learning from mistakes is not part of the program at the moment. There are some limitations to the use of simulator, however. On the other hand, if you're trying to get everybody to a baseline level of competence, you're not really worried about learners on the high end.