She was there to support players and keep their phsych in top condition, the moment the game kept people inside Kayabe most likely forced her to stop for his 'sick game of death'.

After regaining her memories, she tells her in-game parents that she had become melancholic when the death game began, as she wasn't allowed to comfort players and was forced to continue monitoring their psychological parameters, but, after nearly 2 years of only seeing insanity, misery and anger, she finally noticed a couple that showed happiness and joy and wanted to be close to the two to experience their emotions, even though she was not allowed to interact with players.

She was there to support players and keep their psych in top condition. The moment the game kept people inside, Kayaba most likely forced her to stop for his "sick game of death".

After regaining her memories, she tells her in-game parents that she had become melancholic when the death game began, as she wasn't allowed to comfort players and was forced to continue monitoring their psychological parameters, but, after nearly 2 years of only seeing insanity, misery and anger, she finally noticed a couple that showed happiness and joy and wanted to be close to the two to experience their emotions, even though she was not allowed to interact with players.