Who's that wandering the corridors?

Following the sound I heard down the corridors of the deserted school, the sounds of my steps on the tiles muffled by the music that still played in the gymnasium behind me, I slowly creeped up to whoever was there, wanting to see what the whole kerfuffle was about.

Peeking around a corner, I see Leo there, trying to open his locker but failing to do so.
He was unaware of my presence...