Sentry

Sentry handles security duties at the Isle of Grain research complex during the PRIMORD drilling project. He guards cells holding suspects like the Doctor and Bromley, dismisses warnings of infection risks, and enforces isolation protocols by unlocking cells to silence disturbances. He reports murders and breaches to superiors including Liz Shaw, maintaining front-line vigilance amid sabotage, transformations, and facility crises. Protocol guides his actions; he prioritizes order over unverified alerts from prisoners or outsiders.