"In an operations-based exercise, controllers plan and manage exercise play, set up and operate the exercise incident site, and possibly take the roles of individuals and agencies not actually participating in the exercise (i.e., in the Simulation Cell [SimCell]). Controllers direct the pace of exercise play and routinely include members from the exercise planning team, provide key data to players, and may prompt or initiate certain player actions and injects to the players as described in the Master Scenario Event List (MSEL) to ensure exercise continuity. The individual controllers issue exercise materials to players as required, monitor the exercise timeline, and monitor the safety of all exercise participants. Controllers are the only participants who should provide information or direction to players. All controllers should be accountable to one senior controller. (Note: If conducting an exercise requires more controllers or evaluators than are available, a controller may serve as an evaluator; however, this typically is discouraged)". (FEMA, HSEEP Glossary, 2008)