Someone Should Be With You At All Times

Serah didn't originally know about the Secret Common Room.

She received an owl from some anonymous person, which described the location and how to open it.

So Serah did what she was told and found the deserted room.

She found the letters in the fireplace and was curious enough to stick her hands into it and pull out a letter. Once she read it, she put it back and grabbed another. And another. And another. She spent all her free time in the room reading and trying to figure out what kind of people the writers were. She read sad letters and good letters. She read letters of depressed people and of people who were experiencing deep joy.

And she had done this all in complete solitude.

So she was surprised when she heard the sound of feet moving down the staircase. She thought about hiding because, according to Fiona, you should always have another person with you at all times. But they sounded like normal footsteps. "Hello?" she called out.