Fuck. YES. And what would it mean if Bush sees all of that and then sees Hammond later in town, talks to him, and Hammond is pleased that Hornblower's friend, a Lt, is taking notice of him, and he's excited, and he's got this thing about being a man and being treated like one, even though he's so vulnerable in reality. Bush finds them a bed. Hammond would be wearing a suit rather than a uniform and underneath it he's so pale, and his skin's fine from never having to do hard work, and he's been talking about Lieutenant Hornblower.

And that same vulnerability being why he's so harsh on Hammond once they're on the Hotspur

That's an awesome, awesome point. When you're aboard ship, it's serious business, and you don't get it wrong, for Hammond's own sake as well as the ship's. Especially because Bush sees upholding the captain's honour as his duty, too. So the guilt might come in there: what if he's compromised the situation in some way? Made it harder for Hammond?