My concern over your plan is that I suspect as soon as Zachary enters the cave all communication will be lost. It appears that he could go only a VERY short distance before the cave blocks transmissions. It probably will not be possible for him to go in unless either Enoch or Bette come out to replace him.
Your idea of alternating Bette and Zachary is a good one though. It should provide a lesson in selfless teamwork while allowing a little "male bonding" between Enoch and Zachary.
Space Koala Turtel