Remira was no brute. Her eyes were clearer than ever and she knew with the way her target had been holding onto the two victims, there was a high chance that a strike like hers would harm the innocents in her hands as well.
But she still struck as if intent on cleaving Sheva in half. And with her cry of 'DIE' she made sure that Sheva knew this very well.
Anyone in place of Sheva would abandon the hostages and run with their full strength, or use those hostages to threaten Remira. Of course, they would only do such things if they knew Remira, as other Radiant Knights in her place would gladly sacrifice anyone as long as it brings them closer to eradicating curses.
As for fighting Remira with them all while carrying the hostages? It's nothing short of looking for a bad time. They would die under her blade and the hostages would follow suit.