This
scene, acessed via Debug Menu (NOT Debug Room) showing Peach at Booster's Tower was never used in the actual game. This type
of scene, however, would have been used during some kind of battle. How you ask? When Peach talks, her dialogue is in subtitles
and only when you press any button will she progress in speaking. Also, it is located in the monster area of the game. It
can also be acessed via Pro Action Replay (PAR) codes, the 'Fight Monster xx' code. GameGenie (GG) can also be used.
My
guesses are: in the first part, when you reach Booster's Tower you meet up with Bowser. Bowser might have challenged you to
a fight and during the fight, this scene might have occured, thus Peach saying "Did I hear voices?". Though this scene was
turned into a normal scene when meeting up with Bowser in the actual game.
The second scene might of happened when
you face Booster (instead of winning the curtin minigame) and when you beat him, Mario checks the door, sees it is locked,
then Booster tells Mario to step aside then he opens it. Then you go on facing Knife Guy and Crate Guy.