Saw it today.
No lie: We're about halfway through the movie, near the part where things sort of disintegrate for Arthur. And the movie stops.
The fire alarm comes up and I'm thinking, "Holy shit, the incels are rising up."
We exit, calmly, and it turns out the entire building, a multilevel complex, is being evacuated. I don't think there was any violence or anything, but there may have been a real fire. I just caught the bus home and certainly haven't seen anything on the news.
Am debating whether to return to the theater later this week to watch the rest of the movie...