Melissa was absolutely going to tell Anna that she was the one who did the murder in Anna's house because Melissa wants to make life hard for herself. Julian thinks this is stupid and is showing off how naturally diplomatic he can be. His flowery word choice is probably deliberate too because Melissa doesn't have any reason to complain about it now. Also he thinks Anna is way too strict but can't say that directly, so he's using his authority to bail Ellie out of drudgery.