Mental note for next time: it doesn’t take very much water at all to cook rhubarb down.

Luckily it did not.
Other toys were found to occupy their attention.

Laptop flickered and made alarming beep noise again.
Dead.
Call to support, this time with proper screwdriver on hand.
Back in business but lost a tiny screw in the process.
Support fella said, “Just pop into the Apple Store for a little screw.
You should be in and out in 5 minutes.”