For “protect themselves” (rakkhito attā) compare rakkhitatta at SN 6.13:2.4, Thag 2.11:2.4. The use of the term attā here is conventional, not metaphysical. “Personal safety” ( ātmarakṣā) is a paramount concern of kings (eg. Arthaśāstra 1.1.3, 1.21.30, 5.4.16, 7.3.24, 9.6.40, 12.2.10).