It's dependent on ping/computer power. The way it works is that once the blue ghost spawns he instantaneously registers where you are, and if you are at a certain distance (even if you move directly just after) he WILL do the dash attack. If you dash directly at the start of the chamber and if you're lucky sometimes you won't trigger this attack but it's very RNG, except if you have a bad ping (like the uploader here). There are ways to 100% not trigger his rush attack, by going directly to the left and far enough, or using Kazuha E at the very beginning. There's probably videos explaining it. The fact that the uploader there had bad ping unironically made Navia look a lot better in this chamber because you have more time to group the enemies. Usually you can't group them constantly to hit them all at the same time and Navia performs really badly there.
