You should be able to CTRL ALT DEL and close down the amber process that way. Happened to me last night and the layout wouldn't close down.
I seemed to have lost 4 hrs last night, bit of a session
I can't imagine offline again to be honest, it's so much more realistic. A machine errored on me so I quit out and when I reloaded it was in the same error state, it was like waiting for a technician to come over to reset the machine. Though the error was due to me not happen the latest amber update...
I'm going to have a mess around with my Cluedo Super Sleuth layout that I did for mfme, see if I can puzzle it out and convert to amber.
J