I think, the amount of 5mm is more of 'cry-out' amount, instead of base on solid calculations. There is no set rules to use for 'Phychological damage' anyways. I don't know what lawyers use to come up with an amount, but in this case, I think the lawyer is asking so much money to create a social effect, to make a point that he thinks this case is so serious.
This doesn't mean 5mm is a reasonable amount, doesn't mean they can get it either.