After Myrtle's death and the rumors about the Chamber of Secrets, prefects and head students were asked to do a few night patrols. Tonight, it was your turn

You peacefully walked through the dark hallways when you found yourself walking past the same bathroom where Myrtle was murdered... by your surprise, you weren't alone, you bumped into Tom Riddle.

What was he doing here? Past curfew at a 'crime' scene?