She shrugs anything but casually. "It should. Hearts or heads, that's usually the way." Thankfully. Saya had to kill her own kind with direct blood to blood contact, this is much easier.

When the three vampires dash into the mouth of the alley, Saya moves. But saying "Saya moves" is like saying that the universe is vast. She vanishes from sight, appearing just behind one of the vampires that Katsuki's blast didn't catch, and a second later its head falls from his shoulders. She moves even faster than the vampires do; the prerogatives of being a queen.

She turns, sword flashing, waiting to see if Katsuki has the other two or if she needs to step in and hold one of them. He deserves to take this out on the creatures that turned him.