I think the way McGann plays Bush's response to that telling off by Hornblower is a thing of magnificent subtlety. You can see it in his face, and the way he's wiping absently at his eyes seconds before HH even says anything to him.

As demonstrated in your icon lol ;) He's bracing himself for the 'scolding' & doesn't argue back; he accepts what Horatio's telling him but at least he can redeem this near the end :D I was glad he got that chance! :)