Guard (The Inforarium)

A guard protected the Inforarium's illicit information from being tampered with or stolen at one point during its operation.

He responded to a data core breach incident caused by the Eleventh Doctor. However, he did not know the Doctor had already set the ultimate protection system in place to cover his tracks. Each time the guard tried to send out an alert that the Inforarium had been compromised, he was presented with a hologram of the Doctor explaining how he was deleting himself from every database in the universe. The Doctor wished to be alone, and was not pleased that the Inforarium had distributed information to his enemies. Because he was unable to wipe himself from the Inforarium's records, he memory-proofed it instead. The guard was incredulous to believe him, not noticing he had been thoroughly duped into replaying the same hologram every time he noticed the data breach, and would continue forgetting what he had seen.

It's entirely possible that the poor fellow will eventually die of malnutrition if the loop he's stuck in isn't broken at some point. (HOMEVID: The Inforarium)