The solution is to talk to the moving (walking)Bidoofs on the left side of the room, starting from up to bottom, in that order. You need to memorize where they are when you enter the room.
hey it works! Thank you very much! Desolation's puzzle has no mercy despite it's still early game. Strangely, I'm fine with other puzzles. Maybe I just hate Bidoof SO MUCH. Thanks, again anyway~
