Research has found that leaders with a high task orientation are likely to emerge in both highly structured contexts like a group that works to maintain a completely automated factory unit and highly unstructured contexts like a group that is responding to a crisis.
I always found it very interesting to hear from or about someone who stepped up in a crisis or high stress scenario. Especially if that person is not regularly in a leadership role. In a high-pressure group setting finding the nerve to not only take initiative but also direct others is impressive to me. Its also interesting that the others who didn't step up are usually willing and receptive to the directions of someone else even if they are a stranger. It seems the higher the stakes the quicker everyone falls in line and moves once someone has stood up as a leader even if it's a self-appointed role.