Emilia runs upstairs and into Dietrich's room to hide as she sobs loudly. She knows that she was wrong and acting rashly just now. And understands that she acted impulsively a lot before but it wasn't her intention to keep putting herself in danger.
However, nearly being the cause of Dietrich's death as well this time has brought the revelation that her actions have been truly idiotic. Had she lost him today, she never would've forgiven herself for it.
As Emilia calms herself down and thinks about the many mistakes she has made in both her past and present life, she makes a decision. She searches around the room for a pen and some paper and quickly writes a long note before setting it on the nightstand and sneaking downstairs.