Following Gyre into the depths of her foreign planets cave system, her mission kept secret until she is uncovering it through every new tunnel only comes to light with her handler's revelations.  22 cavers failed before her. Credit to the author you feel how claustrophobic the spaces are, it’s a nightmare thinking of the unstable rocks she was under, how easy it would be for her food canisters to give out on her rewired organs. She can’t leave the suit, and it capitalizes beautifully on that premise.