Note: The various branches of even more various militaries, not to mention numerous civilian organizations handle the who-reports-to-whom of heirarchical titles differently. On the tall sailing ships that plied Earth's oceans the bosun (which comes from boatswain) often functioned much like an executive officer, and that bosun would immediately take issue with Thurl's comment. Said bosun would also take issue with the acme of 19th-century ocean-going technology being used as a ferry, but that's beside the point. For our purposes, Thurl is envisioning a circumstance in which he reports directly to the top of the local command chain, and would never set foot, virtual or otherwise, on the ferry or ferries whose boatswain or boatswains report to him.
The point is hardly relevant, because Petey's Laz-Five Waiting Room only requires exactly zero ferries.
In short, Thurl's joke likely only makes sense to Thurl. That's fine, because Doctor Bunnigus didn't get a chance to hear it.