Re: When did voyager go wrong?
They easily could have left one of the side hallways off the main corridor set with "damage" dressing, which could have been seen during full-length walk-and-talks. One episode I watched had Janeway and Seven start at the far end of the corridor near the cargo bay set, and wind up just outside the unseen engineering set. Either UPN's nosebutting prevented it, or they simply didn't think of it at the time.
Dr. Howard, Dr. Fine, Dr. Howard: For Duty and Humanity!
--Men in Black, 1934.