As soon as the first vampires appear, Saya vanishes with her sword up and flashing in whatever small light there is. Vampire heads start falling from their bodies so it's clear that she's still there, just moving faster than should be possible.

Some vampires slip past her because as fast as she is there's only one place she can be at a time.

One gets a lucky hit on her and she flies into the wall, drops to the ground, with the back of her shoulder showing scrapes and small injuries that heal over instantly. And then she's back at it, making a truly impressive collection of vampire heads on the ground. Gross, but necessary.