In the second Harry Potter movie, when Harry was in the hospital because of the Quidditch accident, it was nighttime, and he heard monster noises and it was going to get someone and then he talks to Dobby. Dobby then disappears and the teachers bring in the kid with the camera that got petrified.
We know he got petrified only few minutes ago because of the voices. So why was Colin Creevey wandering the corridors late at night with a camera?