Sentry

The night watchman assigned to the relic room, Sentry performs his duty with sleep overcoming his vigilance. His failure contrasts sharply with the Doctor’s quick-witted bypass of the defenses, highlighting a lapse in discipline where thoroughness and alertness are expected. This single moment frames him not as a protagonist but as an emblem of institutional oversight neglect, his presence reduced to a cautionary backdrop against which others’ competence is measured.