Shocking CCTV has emerged of a woman sabotaging critical infrastructure just hours before she allegedly tampered with equipment at two Sydney hospitals — with a patient dying at one of the facilities.

Vanessa Moulton, 42, is accused of entering Kareena Private Hospital on Kareena Rd in Caringbah, in Sydney’s south, about 12.20am on Tuesday, and allegedly cutting both the water and gas mains before activating fire hoses.

WATCH THE VIDEO ABOVE: Woman charged over hospital security breach.

Police allege she then scaled a wall to gain access to nearby Sutherland Hospital and switched off the gas main about 1.30am.

CCTV footage obtained exclusively by 7NEWS appears to show a woman switching off high-pressure gas and water mains at a Caringbah unit block before walking off towards Sutherla

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