Just had a moment of extreme panic.

I heard this high pitched whine, and then a grinding sound... and thought it was coming from my computer.

I turn my head and look at it, and all the lights are off, the fans aren't turning!

...then realize I'm actually on my work laptop right now. The tower computer is off.

The sound is my neighbor putting screws into the wall right behind where my computer is.

It was maybe ten seconds of absolute terror.