Have a look on the SD card for a wav file called lowbatt. If it makes the same sound as you’re hearing, then for some reason the Proffie thinks it’s not getting enough power. It could be caused by a short somewhere which is sucking power from the battery by getting hot.
I would use the test meter to check for any kind of short that shouldn’t be there between any of your connections. My Getting Started with Proffieboard guide gives a few pointers on what to look for: Dropbox - Getting Started with Proffie.pdf - Simplify your life
Also the saber switched off when you moved it. If you keep it perfectly still, does it still switch off? If not, it may be a config issue where you have an overly sensitive gesture control.