Ah, so the system for figuring out where to set my foot down for the next step and how to carry my center of gravity to maintain stability while I get it there is down (at least as of scheduling this at 0510)
I’m pretty sure now that that time I fell on my face trying to make a 90° left turn, breaking my nose and severing a facial nerve such that I have a dead strip from my left eyebrow to lip between the eye and nose (but am now again able to maintain a complete mental model of face-in-the-world by backfilling from other sources, apparently, including nerves deeper in the flesh) was from a combination of this and the failure of the systems for understanding 3D motion on multiple axes
Specifically, I think I tried to make that turn by roll instead of yaw