Three of the restaurant staff survived. They were Paul Maugé (clerk) and the two female cashiers, Ruth Bowker and Margaret Martin.
According to Maugé, the male staff were kept below decks by stewards. Nobody knows who authorised this. Maugé and the Chef, M Rousseau, made it to the boat deck, perhaps because they wore ordinary clothes and were taken for passengers. Maugé jumped into a boat, but Rousseau was big fat chap and could not, or would not, jump.
To be fair, many of the stewards who held them back very likely were lost also.