It's Not a One-Man Mission
If the mission is critical, trusting it to one man is folly. To meet the objective, time, effort, and money have been spent to make an architecture with no single point of failure, so having a single person managing it violates the objective. Personnel are part of the architecture.
This leaves us with more than one man and in all fairness a decent-sized multidisciplinary team. Although in large teams, it isn't cost effective to educate every person involved on every aspect of running the system—that is, after all, why it is called a multidisciplinary team—it is vital that the lines of communication be kept open so that responsibilities and knowledge are not strictly isolated.
As soon as you lose respect for any one of these key aspects you will be bitten.