Sly, you'd better be on your guard here. My paranormal scanners show this place is really haunted!
― Bentley warning Sly about the ghosts in the area
Bentley contacted Sly to warn him about how haunted the area was, as indicated by his paranormal scanners. As Sly pressed forward, he came across a gravestone that was continuously spawning ghost rats. Upon smashing it, the ghosts stopped appearing all of a sudden, leaving Bentley to believe it was some sort of ghost generator. By smashing them all, Sly would be able to make it through safe.
Okay. Okay, this is kind of a guess, but try 1-2-8.