Tannenbaum Tower

At the top floor of the tower, the two of you find a door containing an unusual lock.

Assuming that each row corresponds with one of the previous floors, you realize that many of the answers would fit in to the tiles of the lock, but not all of them.

“I’m not sure I can figure this one out,” says Cobalt, “what about you?”

You ponder the puzzle for a moment, asking yourself if anything you learned upon reaching the North Pole could help fill in the blanks and solve this problem.