I would think the benefits of getting such a deep reading through undiggable terrain is that you wouldnt be wasting your time searching the immediate area or wondering if the dog had exited unseen,as for rescuing a dog in undiggable earths and at undiggable depths,I think its up to the dog to work it out for him or herself how to get out,harsh I know but what else is there to do but wait.Luckily there are very few death traps in my area though accidents can always happen.