Ah, I get it!
I was doing an HSE Inspection of a Drillship in India and went into the room that had a meat block used for chopping up meat and fish. I switched on the lights and watched the meat block shimmer as the 1,000 plus cockroaches that were covering it headed for somewhere less illuminated!
When I shone my Maglite into the cracks in the meat block a number of cockroaches looked back at me and I decided, there and then, to become a vegetarian (or "flexitarian" due to the limited time) whilst I lived on the ship!
PS
When I discovered that there was an outbreak of scabies on the same vessel, the Medic assured me that my bed linen and work clothes were washed along with the ships Officers and kept separate from the crew! I was not reassured!