In 1940, she was assigned duty on board the before assignment to the US Naval Hospital at Canacao, Philippines Islands in July 1940. After the attack on Pearl Harbor and start of the Japanese war in the Pacific, Canacoa Hospital staff and patients were evacuated to Manila and Bataan under US Army supervision. As the lone Navy nurse on her team, Bernatitus treated American, Filipino, and Japanese wounded from the Japanese siege between December and April.