Here "Turn" means to turn around or turn away from the king. See how you translated this in [1 Samuel 22:17](./16.md). Alternate translation: "Go and kill the priests ... went and attacked" or "Kill the priest ... attacked the priests" (See: [[rc://en/ta/man/translate/figs-idiom]])
Possible meanings are 1) Doeg killed all the priests himself or 2) the word "Doeg" is a synecdoche for Doeg and the men who went with him. Alternate translation: "Doeg and his men turned and attacked ... they killed ... They put to the sword ... they put to the sword" (See: [[rc://en/ta/man/translate/figs-explicit]] and [[rc://en/ta/man/translate/figs-synecdoche]])