Yeah, I read that quote about the Bob-o-later, but never considered that the "empathy" test would extend to the whole level. After all, there's not much reason to go deep into the dungeons except to get some ammo and watch the Bobs die. Perhaps that's why the green Bobs cling to you: to test how long you can put up with them before you start killing them. Although, that all seems like a silly test to give to Marathon player who usually don't hesitate in killing Bobs.
What you pointed out, though, has given me another possible narrative interpretation for the dungeons. Perhaps they are designed as a kind of test that weeds out the weak. Any individual who can't resist his instinctive urge to escape (or who values freedom more than life) will die and thus the survivors are the ones mentally prepared to subvert their instincts and serve the Pfhor. It reminds me of what Tfear says on the next level, "The primary function of intelligence is the subordination of our instinctive desires, the mark of a strong species. Which is why your kind will serve well the needs of the Hindmost Creche."