Definitely not TL-note material but I guess a little write up wouldn't hurt because it's still something that gets lost in translation. Anyway, the original title is a reference to the first OP of Gundam 00 season 2 "Hakanaku mo Towa no Kanashi". More specifically, it's a play on one of the lines in the intro "憎しみに変わっていく前に…", with 憎しみ (hatred) being swapped for 肉染み (meat stain), since both share the same reading "nikushimi" (though I doubt the latter is actually used anywhere outside of puns like this but that's beside the point)