Last update... the jar of rye berries has suffered the same fate and is also lost. Such a bummer, I I have a suspicion that my mistake was in taking the lid off to get the above picture before placing it inside the still-air box. Ah well, at least I have more knowledge of what I can do and what I shouldn't do. It was fun to see what would happen, and next time I'll get them started in a properly sterilized jar immediately instead of messing around with multiple transfers.
Meanwhile my oyster mushroom spawn should be ready for fruiting bags soon, so I'll focus on them for now before trying the cremini again.
Some parting pics of the destruction. Please avert the eyes of any small children, they shouldn't be exposed to this travesty...