Sorry I meant to say "Why she can't."Because she's shown greater speed than him.
It's not any route, Langris power is deleting space, it's not an attack with a set strength that can be blocked by brute force, it's the same as a teleportation spell, that simply teleports things (or parts of things) out of existence but that can be dodged because Langris cannot make the portals appear right on his target and must instead launch them in the shape of spheres.
Either way he doesn't stand much of a chance.