That was actually kind of a neat plot device I guess you could call it? I almost want to see something like that in a regular manga, instead of a one-off. Maybe the so called 'Heroine' in that story would be one of the scheming evil types, or if not evil, at the very least heavily delusional. The type seeing their surroundings as only a game, and their peers as only NPC's. So the Villainess who isn't a villainess at all in nature, fakes her own death and pretty convincingly at that.
If the Heroine of that story had some kind of hypnotic effect / power, maybe the mental hit of seeing the villainess die could snap the hypnotized "targets" (or whatever they're called, i forget the word) out of her hypnosis. Could lead to some intriguing political strife, since the villainesses are usually high ranking nobles' daughters, etc etc.
Basically we'd get to see all the capture targets who the heroine won over / hypnotized, we would get to see them properly react and cope with the loss of the villainess, who in this hypothetical case is not a villainess in nature, and all these characters know that but its too late now, etc etc.
Got the ol' noggin joggin' this one did.