Why this person run at most higher speed in dungeon?

[psttiti]

https://www.youtube.com/watch?v=DgxCLlyrMd4
I see that he dash so fast and there seem to be effect for it too.
my character still running slow after all ally rank are already at max 8.

[Emerald Lance]

Press the dash button. On controller, it's the right trigger; I don't know what it is on keyboard and mouse.