Most people that start fires hide in the bushs and wallop the clown while watching they are mental cases
In this case, he was getting his show as it took place.
All the people were fleeing and trying to help friends.
Then when it all thinned out, the “fun” part was over.
He killed himself.
Was this all he wanted, just the thrill of killing and watching the panic?
I honestly don’t know, but I’m not convinced we can rule it out.