The only problem here is, the poor clerk getting scalded in the face isn't particularly funny. This psychotic needs to spend some serious time behind bars.
He could have been disfigured by this or his eyes could have even been damaged. Throwing a scalding hot substance in someone's face is a serious assault. It used to be that violent, crazy people could be locked up for their own safety and the safety of others. But now they have more rights that peaceful, sane people.