Three times before this. ( and truthfully, he doesn't think he can die — or, more accurately, doesn't think khonshu will allow him to die until he's done with marc. )

My religious duty. ( a pause. he thought he'd explained it adequately enough, but apparently not— ) I protect the travellers of the night from being harmed. ( not just at night and not as black-and-white as 'protect from harm' sounds, but it's the general gist. ) It doesn't end simply because I'm no longer home.