Ran a yum upgrade, and following this yum hung. Opened a second shell, and found the attached error in the Mysql Log. Tried to restart with identical result: instant crash. Other nodes don't even see attempt to re-connect. Only way to fix it was to move my /var/lib/mysql directory and redo the SST.
Please let me know if I can provide any further info, I've tried to preserve as much as possible to help out with this.