The wording of his first look at the casualties BSOD does rather imply Slaine thinks there wouldn't have been casualties if he'd just run away or surrendered. Which... isn't how these things tend to go. (Of course, he's BSODing, so we shouldn't expect him to be working all that logically at this point anyway...)
Who cares about those useless pieces of trash? Hasenvalia can have them.
Well, the next army you put together would feel a lot better about things if you hadn't just thrown away the survivors of the last one...
Ignatov remain the masters of Tsundere Diplomacy!
Sergey: "Your majesty, I have behaved very inappropriately..."
Slaine: "Then I shall punish you with late retirement!"