The solution:
I then unplugged the keyboard and mouse from the AppleVision monitor base, (instead plugging them into the back of the computer), and disconnected the ADB connector twinned with the monitor cable. I then rebooted into MacOS and found that I had lost all of my monitors and sound prefs. I reset these prefs via the Monitors&Sound control panel to what I wanted and then restarted. On restart there was a brief period at 640x480 but then the monitor switched immediately to the set resolution and presented me with the MkLinux booter. When I selected MkLinux my term was at the res set previously in the MacOS.

In summary:
Disconnect the ADB cable from the AppleVision monitor, and use the built-in port on the computer instead.
lefebvre@med.mcgill.ca, hollis@andrew.cmu.edu