that gratuitous sci-fic/horror shit of Shiro’s prosthetic literally eating its way up his arm and bursting through his skin??
Seriously, he was this,
And then he became this,
There should be little doubt left about (1) just how disposable Haggar considered this body (this person). His task here, is to burn himself out and die, while making sure Keith goes with him (which does cast an interesting light on how when this cannon comes out, Keith doesn’t immediately get vaporized, but that’s another post for another time).
And there should be equally little doubt that (2) regarding the more indirect attacks Kuron has brought to bear against Keith (the verbal abuse, the destruction of their surroundings, the lack of restraint or breathing room: things that demoralize), Scorched Earth–with himself as the earth–is definitely among them.