Understand that the external context means understanding the impact the following external factors could have on the RM process, its goals, and its objectives:
The business environment and its customers, suppliers, competitors.
The legal/regulatory/compliance environment: laws, regulations, industry standards.
The threat environment: threats, known vulnerabilities, attack vectors.
The support environment: government agencies like NIST and DHS, professional associations like ISSA, and service agencies such as Security Focus.
Perhaps other factors known to the subject-matter experts that make up the team.