There's more difference than she might guess. Not that Druitt knows all of the finer details about how the Observers work, but for all that their methods are more than a little bit similar to that of the Cabal, they also seem to be more... indirect. Or at least, to involve less overt experimentation and somewhat less genetic manipulation, in so far as he can tell.

(There's also the fact that he spent a not insignificant amount of time wiping the Cabal from the face of the Earth, but that particular detail isn't one he wants to get into just at the moment, given that he has a sneaking suspicion Ashley doesn't remember anything of her time as one of the Cabal's soldiers.)

"There's a bunker, underground. One that's very distinctly been meant as a base of research."

It's also abandoned, but that doesn't change the fact that it's there, nor that it must have seen some use at some point.