A case of the trots due to some bad Chesapeake Bay "ersters" for dinner? I spare you the details, but there have been rare times I've been - err - forced by nature into a "MAYDAY" extended vacancy from a post (none aviation-related). It does show why critical posts need backup staffing.
From the flight deck perspective, after the first "What the hell...?" moment and a quick mental gear-change, the only real operational risk, I guess, was something getting onto the active in the dark. I'd have been just that extra bit vigilant.