It sounds like you may be focused too much on the heat, which may have been just a coincidence with the crashed screen. Has it happened again? I had a crashed screen a couple weeks ago but it happened in the garage overnight. I managed to get it going again and a software update with the new Linux kernel showed up the next day. So I'm speculating that the system might have crashed while trying to download and validate the software package. Did you get an update shortly after this happened?
Hmm interesting. I think I did get an update a couple days later but not on that day (I think)... But even if it crashes (which is not unheard of), it would reboot in about a minute or 2. Not like this, totally dead and having a message on the cluster gauge like in the pics above...?