Sometimes, when things go wrong, they go really wrong. When Harry's name comes out of the Goblet of Fire, Dumbledore hesitates - and then the Potters' world gets turned upside down.
Late at night, in a draughty castle, it would be quite easy to become lost in your own thoughts with your footsteps' echo. Lily enjoys falling into her mind, on occasion - and finds that James has been indulging in an occasional fall himself.