You peer down at the floor, but don't see anything, and it seems that the buzzing noise has stopped. What the heck was that? You're still really curious about what's in the cabinet, but jumping blindly into danger hasn't been going well for you lately. You quickly assess the possibilities.

1. Something inside the cabinet slammed it shut, and doesn't want you inside.
2. Something OUTSIDE the cabinet slammed it shut, and doesn't want you inside.
3. Something slammed the cabinet shut, but it's actually an elaborate mind game to lure you inside and, I dunno, eat you??
4. You're actually perfectly safe, and it was just a very strong gust of buzzing wind that closed the cabinet.
5. The cabinet has achieved sentience, and doesn't want you inside of its private areas without its consent.
6. Ghosts???

Gosh, they all sound equally plausible. This calls for some closer investigation.