Hi Moe64, not sure what "research" you`ve done on varanids, but ALL animals react to us on their terms! In my opinion, monitors are highly intelligent, responsive animals. Yes, of course it`s hard work, and no guarantees, just like with any other creature, but here`s the difference with them as opposed to most other reptiles; they LEARN to a greater extent. Of course, we should always bear in mind the medium/large species are extremely powerful, and even accidently, can cause injuries, but the Tegus are powerful too, and no guarantees with them, either.
ALL animals can react defensively in the blink of an eye, "domestic" or "wild", no difference!!