What the hell happened to the MC that always had his priorities straight?
What the hell happened to MC's talk-no-jutsu?
He could have shut her delusion down immediately by telling her his true feelings about her - an annoying pain in the ass.
He could have reminded her that dungeons are properties of the Empire and her destroying one would cause a huge political issue.
What we got: "I cannot permit you to destroy the dungeon core", "I already have a partner", "What should I do?"
Seriously?