...I think that refers to "Quiet" from Metal gear solid 5 and honestly, her character seems to be there mainly for fan service and the excuse for her not wearing anything other than underwear and stockings (because she would die if she would wear clothes that cover more) does seem like an excuse and nothing else. But I haven't seen the game all the way to the end so there might still be a surprise.
(The actual justification has a few holes since the other people that underwent the same treatment wear clothes and even armour and all in all it gives me the impression that Kojima and his team started with the idea of having her dressed revealingly and thought of a reason afterwards.)