Turns out the fucking power brick was unplugged, and none of my alarms - not the 85%, not the 10%, not the 3%, none of them.
Best guess: it's a conflict between the two battery monitors.
So I power it back up after plugging it in...and it's then that I realise that even though the last-saved time on my file is 12:09 AM, the data in the file is from 7:00 PM, when I started working on my notes.
It takes an hour to retype one page of notes. I had done pages 12-17 and was done with pediatric pathology.
Now I've got to start over from Cystic Fibrosis.