No less than two lovestruck tantrums and they still take him with them into a dangerous dungeon? Beyond stupid...
There's less complicated ways to commit suidide than bring a proven obsessed flake on your team.
Even less believable is the other, presumably experienced, team members actually letting this happen.
After already having seen the need to restrain flakey boy, they should have simply stated "he out, or we out.. We're not going to risk our lives by bringing him with. Period."
But seems the author wants to force unneccesary Plot Drama for Plot Drama reasons.