Officers mass, OOC thread.
More or less. Ish.
Both characters are Explorators, but that's a job-title more than it is a rank. It basically means the 'Indiana Jones of Tech-Priests, doing important work yes, but we'd really like it if you'd go and do that important work over there. Far away from us. Thankyou.'
On the ship, 'Enginseer Prime' is the head honcho of the engineering spaces - a bishop in his diocese, if you will and it should be noted that he doesn't work for the Rogue Trader. He works for the ship. Kind of the same way that the Navigator, Astropath and any senior clergy aboard don't either - they're all responsible to other authorities.
That said, they'll generally do anything the Rogue Trader asks them to do, because to do otherwise invites a sternly worded letter to said authorities.
M'lad Dracius there meanwhile, could be technically lower-ranked on the ship - maybe he's the Transmechanic in charge of ships comms or a Magos Biologis running our labs - but of higher station in the Cult.
It's one of the clever, understated things in RT that at first glance, everyone works for the same boss but at second glance, they've all got their own chains of command and areas of authority to balance, so no-one really gets landed with the butt-monkey roll. ^_^