Complex sentence: Off-duty or sleeping crewmembers report to their stations and prepare for action, watertight doors and fireproof doors between bulkheads are shut and security is increased around sensitive areas, such as the bridge and engineering rooms.
Split into simpler sentences: Off-duty or sleeping crewmembers report to their stations and prepare for action. Watertight doors between bulkheads are shut and security is increased around sensitive areas such as the bridge and engineering rooms.