I'm of the mind that situations like this (non-combat TPKs) call for going the extra mile as a DM. In this case, you could always do something like this:
The rogue wasn't the one who's skill defeated the PCs, it was the sword - a powerful and semi-intelligent weapon in its own right. Why is it powerful? Because it eats and absorbs essences, gaining the skills and powers of those it has consumed, drawing in special spirits by delivering what would be a killing stroke. And, of course, the PCs (who are special by default - they're PCs!) are next on the menu.
So what happens next? The PC need to escape of course, fighting their way toward whatever exits you deem suitable, through whatever landscapes the sword has cobbled together from the memories of its victims (and possibly over the bodies of the victims too). PCs that fall in battle this time are dead, of course, consumed by the sword, but those that survive escape, their spirits returning to their bodies (likely panicking the gravediggers or undertakers).
It might smack of deus ex machina, but you might b able to pull it off. Either way, have fun!