BMPCC4K randomly shuts off during shooting

I'm using a standard BMPCC4K. I'm not using any kind of external power, just the internal battery. I noticed when I was shooting yesterday the camera would randomly shut off in the in the middle of recording!

I don't know why it's doing this to me. My batteries should've had enough charge. Maybe the battery itself is slipping around in there?

On a side note, what would you recommend for an external battery pack?

I've recently become a fan of these for external power.

https://www.bhphotovideo.com/c/product/ ... ttery.html

The only time my Pocket has ever turned off is when I actually did run out of power. You're saying you can turn yours back on without replacing the battery?