This is simple, it really doesn't need interpretation, but... It's about murder, obviously "die die die my darling, don't utter a single word... Just shut your pretty eyes, I'll be seeing you again, I'll be seeing you in hell", he's murdering "His darling", it's pretty obvious. "your future's in an oblong box(a coffin)" "and now your life drains on that floor", a reference to blood. It's about murder...