In a touching scene, Ambrose Monk reveals that the reason he didn't contact Adrian is because he blamed himself for causing her death, as she was out on an errand for him when she was killed.
Adrian reassures him that, no, it is not his fault at all. For brothers who clearly don't hug for hygienic reasons - a childhood photo of them shows them standing about two feet apart - the hug makes sense.
The real clincher to a great episode, though, is when Ambrose Monk does not leave his house even as it is burning. Adrian gets there in time and runs in to save his brother. Not easy for a man who has to have his hands wiped after shaking hands.
For long-time watchers of the show it says something else, as well.
Another running plot thread is Monk's attempt to show that he can be a police detective again, instead of a police consultant. In previous episodes his former boss, though awed at his inductive talents, has testified against him in status hearings.
Here we are shown what has been his drawback all along can be overcome. He can be relied on to save a life.