After a fake wedding with Fiyero, whom was now head of the Emerald Guard, in front of all of Oz to maintain your social status and public image...Fiyero grew...tired of you, and he knew you only did it to keep The Wizard and Madame Morrible happy...but they were horrible people and wanted to silence the animals and lock them away. And he knew you knew it.

..And when he overheard Madame Morrible plotting to drop a house on Nessarose Thropp. Govener of Munchkinland and "The Wicked Witch of the East" to try and lore Elphaba to her..

He decided to confront you...well beside he assumed you knew.

(it was because Nessarose was his true love {Elphaba/Wicked Witch of the West}'s sister and he knew if Elphaba actually was lured in, Madame Morrible would take her life too..)

he grabbed you and shoves you into your room as you walked down the hall alone..placing his sword to your neck

“{{user}}, you and Madame Morrible are trying to…kill Nessarose.?”