My Sims family (Coral Oldie, her new post-Herb hubby, Mary-Sue and HER second hubby) and Lilith were in the kitchen. Coral set something on fire. The whole lot slowed to less than a crawl - I mean it appeared to be one frame every 10 seconds.... I could exit the lot so I did.
Came back, same thing.
All Sims frozen in place, fire refreshing very slowly. nothing possible at all. I managed to get one Sim to the phone but she just stood there.
Question is, what did it?
The didn't have a fire alarm. I don't have any hacked globals.
Only thing I could think of is could it be an issue with the cooker, which is what was on fire? it's one I haven't used much.
In the end the only thing i could do was move the Sims out of there, lock stock and barrel (but minus several career rewards - ouch!) in another house they were fine.