I think he meant "clandestinely". Don't know how you could physically work for anyone "subliminally". Just being nit-picky;-)
I'm pretty nit-picky about words, too, but I think "subliminally" might actually work in this context. If I make a statement that's meant to fly under the radar of consciousness and subtly plant an idea without actually stating it, that could be called subliminal, I think.
For example... suppose I was to write "I HATE WAVES" in bold red Freddie-font. Well, I've never done that and never will. ;)